Day 4 complete

2022/1.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int comp(const void *a, const void *b) {
+  int n = *(int *)a;
+  int m = *(int *)b;
+  return n - m;
+}
+
+int main(int argc, char *argv[]) {
+
+  if (argc != 2) {
+    fprintf(stderr, "USAGE: %s input_file\n", argv[0]);
+    return 1;
+  }
+
+  FILE *fd = fopen(argv[1], "r");
+  if (!fd) {
+    fprintf(stderr, "Error opening file\n");
+    return 1;
+  }
+
+  char line[50] = {0};
+  int idx = 0, elves[1000] = {0};
+
+  while (fgets(line, sizeof line / sizeof *line, fd) != NULL) {
+    if (strlen(line) == 1) {
+      idx++;
+    } else {
+      elves[idx] += atoi(line);
+    }
+  }
+
+  qsort(elves, idx, sizeof(int), comp);
+
+  printf("Elf with the most calories:     %d\n", elves[idx - 1]);
+  printf("Elf with the 2nd most calories: %d\n", elves[idx - 2]);
+  printf("Elf with the 3rd most calories: %d\n", elves[idx - 3]);
+  printf("Total:                          %d\n",
+         elves[idx - 1] + elves[idx - 2] + elves[idx - 3]);
+
+  fclose(fd);
+  return 0;
+}

2022/2.c

@@ -0,0 +1,117 @@
+#include <stdio.h>
+#include <string.h>
+
+struct RPS_Game {
+  // Part 1 Rock / Part 2 Lose
+  const int X;
+  // Part 1 Paper / Part 2 Draw
+  const int Y;
+  // Part 1 Scissors / Part 2 Win
+  const int Z;
+  // Outcomes
+  const int draw;
+  const int win;
+};
+
+// Part 1 - Calculate score
+void process_round(struct RPS_Game *game, int *score, const char opponent_move,
+                   const char my_move) {
+
+  switch (my_move) {
+  case 'X': // Rock
+    *score += game->X;
+    if (opponent_move == 'A') {
+      *score += game->draw;
+    } else if (opponent_move == 'C') {
+      *score += game->win;
+    }
+    break;
+  case 'Y': // Paper
+    *score += game->Y;
+    if (opponent_move == 'A') {
+      *score += game->win;
+    } else if (opponent_move == 'B') {
+      *score += game->draw;
+    }
+    break;
+  case 'Z': // Scissors
+    *score += game->Z;
+    if (opponent_move == 'B') {
+      *score += game->win;
+    } else if (opponent_move == 'C') {
+      *score += game->draw;
+    }
+    break;
+  }
+}
+
+// Part 2 - Find move given a desired result, then calculate score
+void find_move(struct RPS_Game *game, int *score, const char opponent_move,
+               const char result) {
+
+  char my_move = '\0';
+
+  switch (result) {
+  case 'X': // need to lose
+    if (opponent_move == 'A') {
+      my_move = 'Z';
+    } else if (opponent_move == 'B') {
+      my_move = 'X';
+    } else if (opponent_move == 'C') {
+      my_move = 'Y';
+    }
+    break;
+  case 'Y': // need a draw
+    if (opponent_move == 'A') {
+      my_move = 'X';
+    } else if (opponent_move == 'B') {
+      my_move = 'Y';
+    } else if (opponent_move == 'C') {
+      my_move = 'Z';
+    }
+    break;
+  case 'Z': // need to win
+    if (opponent_move == 'A') {
+      my_move = 'Y';
+    } else if (opponent_move == 'B') {
+      my_move = 'Z';
+    } else if (opponent_move == 'C') {
+      my_move = 'X';
+    }
+    break;
+  }
+  process_round(game, score, opponent_move, my_move);
+}
+
+int main(int argc, char *argv[]) {
+
+  if (argc != 2) {
+    fprintf(stderr, "USAGE: %s input_file\n", argv[0]);
+    return 1;
+  }
+
+  FILE *file = fopen(argv[1], "r");
+  if (!file) {
+    fprintf(stderr, "Error opening file %s\n", argv[1]);
+    return 1;
+  }
+
+  int part1_score = 0;
+  int part2_score = 0;
+  char round[5] = {0};
+  struct RPS_Game game = {.X = 1, .Y = 2, .Z = 3, .draw = 3, .win = 6};
+
+  while (fgets(round, sizeof round / sizeof *round, file) != NULL) {
+    if (strlen(round) == 1) {
+      break;
+    }
+    process_round(&game, &part1_score, round[0], round[2]);
+    find_move(&game, &part2_score, round[0], round[2]);
+  }
+
+  fclose(file);
+  printf("My part 1 score: %d\n", part1_score);
+  printf("My part 2 score: %d\n", part2_score);
+
+  return 0;
+}

2022/3.c

@@ -0,0 +1,105 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+// Find badges for part 2
+char find_badge(char group[3][50]) {
+
+  for (int i = 0; i < strlen(group[0]); i++) {
+    for (int j = 0; j < strlen(group[1]); j++) {
+      for (int k = 0; k < strlen(group[2]); k++) {
+        if (group[0][i] == group[1][j] && group[1][j] == group[2][k]) {
+          return group[0][i];
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+// Find items for part 1
+char find_item(char *items) {
+
+  int len = strlen(items);
+  int mid = len / 2;
+
+  for (int i = 0; i < mid; i++) {
+    for (int j = mid; j < len; j++) {
+      if (items[i] == items[j]) {
+        return items[i];
+      }
+    }
+  }
+  return 0;
+}
+
+// Updates item_sum / badge_sum when match is found
+void update_sum(const char c, int *sum) {
+
+  if (c > 64 && c < 91) {
+    *sum += c - 38;
+  } else if (c > 96 && c < 123) {
+    *sum += c - 96;
+  }
+}
+
+int main(int argc, char *argv[]) {
+
+  if (argc != 2) {
+    fprintf(stderr, "USAGE: %s input_file\n", argv[0]);
+    return 1;
+  }
+
+  FILE *file = fopen(argv[1], "r");
+  if (!file) {
+    perror("fopen");
+    return 1;
+  }
+
+  char items[50] = {0};
+  char group[3][50] = {0};
+  int item_sum = 0, badge_sum = 0, idx = 0;
+
+  while (fgets(items, sizeof items / sizeof *items, file) != NULL) {
+
+    if (strlen(items) == 1) {
+      break;
+    }
+
+    // Part 1 - find misplaced items
+    items[strlen(items) - 1] = '\0';
+    char match = find_item(items);
+    if (!match) {
+      fprintf(stderr, "Match not found: %s\n", items);
+    }
+
+    update_sum(match, &item_sum);
+
+    // Part 2 - find badges among groups of 3
+    memcpy(group[idx], items, strlen(items));
+    idx++;
+
+    if (idx == 3) {
+      idx = 0;
+      char badge = find_badge(group);
+      if (!badge) {
+        fprintf(stderr,
+                "Badge not found among the following group:\n%s\n%s\n%s\n",
+                group[0], group[1], group[2]);
+      }
+
+      update_sum(badge, &badge_sum);
+
+      for (int i = 0; i < sizeof group / sizeof *group; i++) {
+        memset(group[i], 0, sizeof group[0] / sizeof *group[0]);
+      }
+    }
+    memset(items, 0, sizeof items / sizeof *items);
+  }
+
+  fclose(file);
+  printf("Part 1 - Sum of item priorities:  %d\n", item_sum);
+  printf("Part 2 - Sum of badge priorities: %d\n", badge_sum);
+
+  return 0;
+}

2022/3.txt

@@ -0,0 +1,300 @@
+DsPhSBQQQhqmBDhPDsFwjwsLjlRjlttvjvvtRb
+rNJMNNbrHrtjHLHjvwtg
+fNbNzZdrZnMnMPnQShFPDmnqFm
+QWVCFfQffgQCVZzVVpHsHJBqtpspJFRHqq
+mwDbmnnGNlNcwNDDNRbnNDlJTpBJBtJGtPTLsBGqTqqsqp
+MlSdnScRnnmmDjSdNSdCzvggWzrgzjvfvrgVzW
+gsMljbrjlZlWcWMJrWwTwbmwQbmmLDQQLhwL
+CdgpzdgpgnfThHfFRwhfRf
+SptgpSpnCNpVSGNPvPGSddcMWjMrjqBsJcWqMcBWcVlZ
+JcJLQQFWhQJPJpWcwjHvMQvnnlMvzBHd
+tCtGZrmVRmVGTVTtCfRTCHHNNvdNzmdMvMlNzvwdvw
+CTGGRftfSGtGTGDLbFchSgSWWWcM
+QcMFQrvrQbvtczbVbjbMzZzRpqmDDmqqnNzCDCDC
+SHHfPJssGLPSdHThLhHdRmqNmNssnNmNCNnpjmsn
+LhLJfTdLJwfgPTdfGccrtjcMrccwvcrrFr
+jFLLLqDGjbtqLCChpMMhMBvpwMTmffpZ
+ZnJHRncHHgnrsrZffTdMdMBfmMvfvR
+NWWPnZrVHrZPCDDQtzDCPLCq
+jpFjvBZhDFHZdwcmslcslBLLNl
+dVtTVVCzzfrrMPNLLcnVcPLRns
+CrzWzTqdWtGCzJtbJCrMjjDFHZQjZSpvFGFgHhHp
+JjJqMctnhtDZDQtf
+TrFFlrrCCHPwHwlPHFPzDhsffQQDsVfWwVJQJB
+HHHGdFlHldTpCCFFlLHdCRJccMnqvqMgnNjjMjjvLMLcSv
+cMfFcMFcrqgJLFZdrTDdthPGsGmtGs
+WwjNwnjjBQzVVQHwRDnmtPGhPPsPnnTGld
+bWHBjWVzpbRzbmScqgZMFcqf
+RJjPTBJhTNNjfPhRBdqtlgdbGldwtCPgdb
+ZmrHHmzpvSvvpzvmvDVCGlWVwCWtGtWCddggqf
+QQpzFrHHQnzHvfTcNshcLRNFJhcR
+QrPQDrppBQmCmFQm
+TzqzsLfmsfSTfqzVLftNdJJNJGCwwGdgCwSGNC
+TVHTfzWsfftsZstnbvrbWbrbppPbrmmP
+BQrfqrLtJnttqqtQBJDDtBnDzRgldhVVpJlgzpzhpzsgslhV
+TTNcPZCvZjmPFZjvPHLlWdNLghVhzzlllpVd
+jcFPbTcZTFcmcjMjjFjbLwbnDBtfqbtBwfwSBnrbGw
+SZJNJtrNzjjNCzlBBmqmQDBBmDBBjB
+PGPbGwhLsnvwnVbGPVMZsDsTBBgcZgBBDBfDBf
+pnnhhvphGVpvRPnJlSFRNNJHZHSdSR
+hbmDDmwnnVGbhmjNrrWwLNLsWBrw
+dMrgvcQqdjlBLlfW
+HzzPSrcHqFHQgzpPcMpQqrtmbbbRhHHVGnZDnVHhVbVZ
+RwtvdPRvSlTQmHHBQBRL
+FjVSjrsFVnFQnTHmnT
+VCVVMrWWjVGgbcNVGCCVdlvfdqfvwbSzwqfwZzwv
+fmPDwJPDFRmRgPdwwwDNwgwPzhSQzVSzVTQdzHZzHhzQMQzQ
+sWtGCWtpcqqpNnQjjzhVTTVQczhj
+tWBGntsCNlqrWswDRfFrbFrPDbPf
+dmzmjcbQjjQztFNqsqBcMJqNPF
+nlTWnClWwQDTVnTrsMsCRBPZRJRJqRJq
+wTrhwpVVvgvlDpTvVWVDdLfzgbLtbzSQLSzzjzLz
+RWZdHvRdBRGbbvCjJnbn
+pqqpSwzpSSbCwPwjlwjl
+gDzzqSVzqrThpDBtRtCZdQRQLrQQ
+GRqTGqtmTVdGHHVVNNlhPlMqbNqNDbqW
+LzQSdFnfznfwBcLcnFppBBDDMPMPhDbhlwbWPlbWMjrD
+QznFnLZFvVvHRgsddG
+BBHBfBHFdSltmWJvqtNtHq
+TQDrrVMzVDnWnNZDJc
+gWzprTCrCMQzGGjjhwFwdffjfl
+LLLSSSzBBlBLsszncCBZSPSMMMpdWTdrmmnfVGVmMfmrmm
+DghttvwhHRvjJthNJwhVtDHGpddMWdMmrMmfGdppjWTfpq
+gbJRthQDDRvwtDhQhDFPcVcbPczLzPBScBBF
+sZsZpTtLCsbspZtTwrCwrwtDmNNdJmmqSJfqmfNGNmHqGdqb
+nQvjTcjQglFVlllMFMVFqWfNqnNHHHdfSfHqfSJq
+hFvvgFcFVzphpTrrwZDp
+qJqfhsBpfSpchpqcrqwCDvvCDQndmpwDtnRQ
+jWHPZWWjZsCmCWRDmQ
+PPzMGHlzMNsPLPlZsllgsNrhNVBqhFVBbBSqFFBFrV
+RnRsFFdSzmgwvQsqwc
+lbgHGMBHlWWWlfWGGBtGwqDpDwmcpMrrqrQDZrMZ
+GGJLBVJbVGjGtHVfJtWGHBLLPdzdCghnRnRnSShgNnhnddhj
+VgzLFjjwhhSwFhVZgRhRgHHCCvdZdrqqCTvBCrqvvr
+ncnNbGMcPpvHFrssdBHM
+cnctcNNbQGWFJctftgVmzShzzwwVwgmwfR
+pFWmSSFGQlvTbwWTwH
+jdBgNhRgMftNBhPbhHnZHlTTZcwZ
+lfBNRjCtCfMjsBfCjgfNBRMppGpJqsJQGrrmmJDpGmDDFG
+GznngnhzccVdgjbbVjVjVbVLwwQJmQMrLTZhJmZLQTJWmm
+pDBSslPCFPCpvCqvpPBQTlQLrdlJWrLJLmrlrr
+psSsBptpCBdjtcjNVcGG
+sssppsmchwspFLtvHhQJMtFb
+rRLDqRVLNSMvFSSV
+WDrLnzrDqzRqRzzfLgRnzrnsssZZZsZBgCwwmBppwBspZc
+MtPbwvzzVtzfsqGGVpdSjsLd
+DnNRCDJBnHJDHDnrDTRcnNZpZSsSLqjpdqqqSMqdddTj
+CFRFRFHgDRnRgMtfFvvwzwvwvzWv
+PNpFPncvvchPpNjpFhvPhPLmBwMgDRRwRgMDhBmLzBDD
+trHSrdTtslWrSWmfzgmMnfBzmn
+JsrQsJHHlsVqTjjpbbNnQNNpGG
+sVQCdsmGlnlCmnGmQQhGCJJNvNjpgqhqhvPgpgPqjpcpcW
+DMSfSbHLHbSDBBzLNvccWRcddvPjNj
+FSwHfTFdFsmJlnTTmV
+FctwtTTCScvShFqtwScrcTSCJQGNndGHWJNQHWHZdgJrJgGN
+jspLlfPlpfsDjBspfllWgdWHQggZHngHNGdsWJ
+lRMpBlPmSFRTcvZv
+TVZpRRVvFRVpTZRfFhFvvzGVwrwwwdDBMwQrgcDtMtDDwZrL
+jsNsWqWjNQCNWbjPMcBLPgBtrdMwdrdL
+SJSsmqlSNljbmlNjsbQVffzGRvzmmVhQpVGz
+BFFMvcwMwwpFFfpbDMqPVgLVgmLDPR
+JtSsSzJssQJJWjRZzgLnDgqLPZgzbg
+dsdtWQWdRGjTRNQNQvGfHCCFpvfGwlCfCp
+zzWGqWnqnwWCvCrHffHRpBpBBRSJzRFFDhSQFR
+VPVsZMNTLsMvPsmBJhllFpFBTJFQpl
+sZtsNsZtdZgjbwggjnbvqr
+QpTvrphmDvvddfcJJHTTncMlMG
+bRZZPRwjgzzlSSjGlnlSJS
+BZzBzssWgwzzwNBsgsPBgszmQptqrrGdvdWmqdhhFQDpQF
+FfMtzSqlDlzfMhPFhPtffNRsCgSgCCGspRpRGSsgsg
+WTcWLTTVnWmrVdLrcHmNGNCZwCCggpgDRwpCnR
+JcdWJHTJWdJdjJccrLvlFltFQQvPFDMjqqlP
+NfjFNNZPDQVJVWpCbQpJ
+lcmdzlmzBtRSTlTTcncsVSbhpLWpWgsWghgsVS
+mBTRRmGccRtBwDbrGPbrMMrF
+VVQqlsGrVsMWBNFNMQHF
+TfzZfDgjgnLGjjztTncCFwwNmdvNcwwNBvHNFwvd
+jzjDgZzjntGJZzCnhrrSlPVsJslpslPq
+dVhpjGPdjHhqHgtHJJ
+sFzrzllQswDwFbcmBlgvZTCgvqTCfgHQJtqT
+nDbBsFzzrrtFrlwzPdSVMWMVVMSnGNLd
+wqJCjqChmwMLmMmprNgG
+DNTtdsdWcHdNspGQggnrgLnQpc
+SZvFftdddDsDTtttTDJNCCwJJZzbbCjwwVPj
+VstwZCwslBZQDBjfDDBDfS
+rvHnmMRrTzmMrmhRppbhDfpjfbjbctjD
+rPFLRLmFvvLvHvTCtqsVVwldGZGPGV
+SNZDJGfvwgMgfgmLmLcmBqgWgQWr
+hPnPTnVGsPRqLWpTmQqQ
+tsbnFhhjhSdGJNCjSf
+QSbGgBjfTCMWFNPFFtDghPrP
+JqHqJVzZzwJJHLlqQptDhPrctpPDtnLF
+zZmwJwdwdvHddVJvZqdzHlfGBbsCmMTsWCBCjsGGBbMQ
+gVmLtpWrFTFBLtpcFNbvhNNnTnvnQRlQQv
+GHjjqsMqwZZJdqGfZjfZGjQDDhvQNzznzRzRwDNbvgzv
+sZGPgssMqHZpPptmCcpCrP
+CZCNNLmwzwCGMZQMQsFNWplvpsJBWpFHBp
+SPbSbDRRbnDqggnbVbVrbRWHJFTlBBcTvWvsPvFpHTcl
+tVgSvqVbnqDdgQzMQMGMmzthCw
+mpbPQlblbwSlfSPGBpBGPpBFgMMtLFSHMLVVDVdtHLNctF
+WnhZsrJhTnWrgZdZgHNLcLtt
+hjCsCWRhjzhTjnWnQBbmPQQPLBGfqjwQ
+BFrzdtmRmpFtFwwmjjzNQllPshqHvjNh
+fWCLLCMJnCDbgfMJhPsPHvqvqVsssQ
+WbLnCZnvprpmZrGd
+gjMzTGBjWFBCCSSrBC
+bddJJndbdJfwPPthrrSSSsFSSg
+NJHbZbbvvWGgjWgT
+dpfphMggHdQcwftMMgdtzWGfGWnDBnmvnVJVvfmn
+CqPFTZPSNCTsZZZRLzGmcGVzDLGvLWBWJm
+TCrTNSScPlplpHrQrQ
+lqrCvhWFvMGWgfHPgLfjfdgG
+zjmbjSnzRzVVRmzBRtwjVQnNLfdPgfLdfTtNLPHTNNpppf
+mbSZRzQRBnnzbQJbmjmSbmVhlslZMrclWFrrqWCWsFhchF
+mpfNshshflNthWfJCBBdmnQbQBZQdn
+VFVRccgGTqTrHTbWBFjJBCFFJCCQ
+PvTDHqHqPPGVqqhwfNlWlDhMltlh
+HmLLgWVjJwhwWLgjjhmVHLLLlSzBlBlSvBvBFGvtdStJSSvq
+TRRrPMsfQTbRRCZRnTMRZZTCcvSccqBqBBlzdFvBqFsGBcts
+bRNPbRCZMCrQNfPLdhVpLDVgDhNHWV
+sPJFDsSsVLgHjLHPbj
+vCnRQhhRQdVQZlZdbHNMlqNNjgjbpbBL
+ChhCCCWTWnnmvmGtztStzScwrcVcFW
+NRBTNDBglSSgDwCClQQSFFHdLLsFbPFFLt
+McpmWccMWHZPcLstbt
+MWnWphVMvvzJzpWJWmVphjrDDBBTRwRDDDRRCnPDnqgg
+hsnnhhLljLPTmZwvdZdZjmmz
+RQNNDpNMSZwvsmqstN
+QFMFRDVDsHSpRpHSMRHfGGGTLhCChBGhBhBFBJ
+TTbltCvClzvzCZtwtwLTtQQQgjNgmjgQRRRQSjQLjR
+HPpnZHcJsdnnfsdVHHSSqghhmqBSSqSmBfNj
+VMJJdnMPrMGVrzvCZwZWCzCt
+CcQnBBCfBvRzDlsS
+PdbPPCbhGGpDSDlDDhvDJl
+HmHWPWdbHnCwCHCr
+JHlmJcMWHQcPmlmJMmMZPfwTTRDfgdDBfRtgQgdfBw
+zVvFrqGjzWGVrqvjvNFpspvVBgNNddtTgghhRTwgdDwwwBfT
+bVFrrvsvjWGVsCsqpSHZmMPJlJnCcLcPZZ
+QrrQZFZnRtnFRTrnlFTtRZwpGGwzGszhjzbsGzzhmjjhhmhf
+SgvpDSJSgPBSDPDNgpggmsMhMmffsMmzfJmzHHMj
+WNVcCPgSSDCddSdWCpNBclCQQFRQQlnTLFLRZQnLtt
+tgvqWqzvntdlzNzzHrbPrMhHMhhrVrjPmC
+FGTGGRGTffcJRpQcJJwmjhPLhjnCQPrLPVQrMr
+SppRSDRwFnJJwwswTDdtzBzqWWzZDldNgtvl
+sjzPjLphMSrlppSp
+fbGqgwTqgVTFFcgGTTGcQvfHQZRlSrSlSmMNMBRNNNrZmm
+MVcFGTFtqjsJLjjtCd
+jVJqTRHjjtDjZnVJVVjnNdwfCFPZmPgCCgCZGCFFrrFg
+LSLBMBWsbBBCgfdrFd
+ShbbzdzQRNNNVhDN
+JwbSRqmSwRwcpmbSSVfhNBTVGGRnNNzRNh
+ZPfQPjZZrffQZszhzTnVGBvntsNz
+rLjggjQgQgFdPQjLFQZgwLMbWccLSwWHqHfSqpwc
+cBhzNpztzHNrpHSHQrhZjZqdJRRgPqjhjqqP
+bQwsMTswwVjdZMVRJM
+vGWCTDCTQvvtlvQQ
+mHVmTTsmzRmRHffmmfMGBzSPMhSWWdDWDSGB
+VNcnNbtqqJbcbvgvWhShDBDPhjgPhSjB
+FrrbCnqJcbCJcFFbnqJlppCTfQmfmZQTLVswRLZp
+rWWppSStfRBLfHPdHHDzlldZ
+QrTnQmmVCqvrvJvzJZPHvzHsDs
+qgMMmrTTCcnQQmCNQNQmgTpwRWRtwtpcBWwjSRSSpttW
+SzWQwwqVbQzwGSfVwffVwbqhFGFFMgGLGMlNMcnNgcvlMg
+ddZHHsrCdBssDsHmChFLNNnMvmNnnnFncL
+rpJJdHZJdZHQSRJbSfVhww
+jLtFhNwNNvHnjFVvQLQLHhfbGDMPfffpllpttZMPPZZb
+VmrqszVmgCWWggbPGclPlZbcZCbf
+JdrTmVTVsqsRJHvQnnhwhBLH
+vpdBvsvdVvSPhvQFCgrRmhjqqRgWcWWgmf
+tJDGbZHbjRHNrrBj
+DnMnzGJJwtzVSzzBzTBSTF
+hZMDbQhMhlMDJrDrPMJRRqGJSvFvSwFSVdvGvwSFqq
+HjjzcRTnpGVSGGFWHH
+pssmjctLzpsRRnhlQbPfPrgDbZls
+FJMhPhnTMGmBFdnmlrfqfCcwlwCwCv
+pjHLsLbjjRHsHsjDjVsgDRjzCnfCfzqrqvwgflcvcvvgqz
+njtpHZnLLQGhTtTWSSSh
+NMddMTDrrjNnrnMWMrlnPwNwftBtGvptGjBHgBgpfCCSfgvf
+mqRqLFZRVFbtgBSCbGWWHp
+LZZRmQhVLLFzZdTQPndPNTTnQW
+CprQrcpqhHhpppchpphdcdpLMRMGsVGGsMsLbZbtbfMRmtbG
+DzlgTjwPTlSSSCDSlggNmMRtbsstsMfbwtVssMmt
+TNCNSBNJJTNPJjCTBDzjlJrvvcQrrhphWBqHhHdqrnrr
+ScbcbglMPRSmvclTlzMTdhVHhhjfdsdhrVDzfjrD
+LJGtpQwpQBBCttJLGqtqGHhPfDdHwjjhrVrhdrdshr
+WCpZQCGqtqQWtQWplZPcvMmgmvPccbvT
+tGWqthqGVdzBWwdd
+BZvZHFFHZrHZvZNRRHHZNHrMMTzRMTdTzbgDVMVssTDTwg
+JnNmrHHNrCGBPPnGGc
+wvFvZBmppBdSLcvshcLrgl
+bTQqJJHJzJjDQjQtzRVJztDHslgNNVLcgSrsSsWrSslWgrgL
+TqHHjQnbHTbbmZBBcFMpmBwn
+ZFCqSlCPdCRTLWWTQQLLQS
+GjggHcvsggHVTVBLnlcpBQ
+hvGhlrtjmjrHHhjsMPFNPdtqMPqqRfCf
+cgRwVfVzrgqqwZctTztFMFMTCdPmmF
+bWJsSJHpTDRDTWMC
+sHHNbshnlJhJjBsjsbnBHbZcqrZZQwqvvZcrwwvRcZnr
+ttgVBtMbttngmHJVpzlzZlppzw
+cPcsRPmPPQfGcccRQSSZzzvzlflzZHvJppzJzT
+sQPSCPPWccWWWqsQqRCQFNRMmnbnjjNbgDdBjhBrdbdDbd
+gSsZDSgdQZgWSgddwLDLLfCDBqvlhBlClqtqjhvBhB
+RMcsVMcsbVsrPrmJcPHHVvfjjCnvvfCqhlqvqqqq
+NFMRRpHPgzszGppG
+WmmZZNJCgCBZCzPvmBCmjWjjqFtFqjFjbVwqwjtt
+ppDMpdMfSfSSNtlwqbqwwq
+dTGDhdnfLMLhfDDpQvZNZgmrmrQJgrLQ
+jrqRqfNNhrVvcTVdpTscpd
+tGWBlLggWGddTspZZd
+JJzWtQgQsDbBgDWsgbFrPrRJNMJMPqMNfHjH
+GdvVbbWsWdvWGDvWZcbFBTBZCzCjwzrhPBJjzF
+nQPfSHnglfpnMSngnMgJTprJCCwwrwCwpTpCFj
+SQQHSttRqggmlVsNcvWdRvbWPN
+WLNLCWLsSJgHFrSHrM
+gDbzRTcmbzPPgPPdtBctfHfrMMQfGFJrhQnMfGJR
+dmmzzqZdDqqTLLwjgZgNljws
+TCqsDHssmDsDGVGlVcMccGDV
+FLntWWnnFzFgzzbtbznLBtlfjGZmcfFGVNFGlVZcMNlN
+PpbLLmpgbRzqpCHwChQqwh
+lVBPVgflgBVVrVTTwgwBPmgflDQjnnGvqjGDDFjGlGnvqHHJ
+ScCLzdCZdbLSbFdFqvDDdGMQGQ
+bchNCLRWSbzCbNRzbWRmsrhQwVVwBhmQpPwpgV
+GmfHCCPqWqHLWLCfRJpbrrbQphwZbZ
+STVDQzNnzMzNdstMDzzNtZwFhrlwVJJrJlFFJRFwFR
+DzSvzstnszMnjQcqggjPqQBcqq
+BzNwLTqwTjrBrljWpBlrQpBpsCGGCtpssCMttDtHsttMDCHp
+mnrJVmRhhvJVcHtsGHMCnZCPZM
+bvSmVbRhbgmmSJflzNLrzqzfWfqBWr
+qsZLqqFNhfrGnJFv
+DVjVmWlcjVjdDTDlbbTDTzmrCnMmJGnHnmCHfJGfvnfM
+lVRdDglTlTgVlVjbWWVzVjvNZqSBsLZNtqRsLBqLqQtL
+ffRRfLVHZHfJHVJcMrMZZwwTzGBBzBTBjGTwrwdSCj
+qmWbWQbqnbvWhbQPGnGNnpvwSzltpBldtSdzllptCSjTTt
+vWsbnbWnNvQQQQvsRRLfJRRVGfDcfV
+PpqrvswPvvvPsNqmDLDttCCcHHZVrCtW
+hgSddBhghQMdbhbwhgSdQgCCctZcDtLntLttCVLtSLCc
+dGzdQMFzQMdgGGlGJMzBgBwRqNNfmmTsvfRfJTpwjmpP
+pcphpdrWDmTgHWMtRWqHRVVH
+SbGcGGQnvNQGvsjBtVHBLjvqVPVB
+lzbQCzbZllSzQslpCJpJJDggcggfDT
+ffrTlhrVrfCsDVTsWzGBBZcBRBqRBWtGtZcq
+QNFmFHrHNSSmSLJdJrNGZLbGjbcBjBGjqcbgjc
+ddQvPnHddnQJHSHSFPdnFfDDTfDMMCrwMlPTwDCsrC
+NBnrNHQHBscvhfBM
+bbGtgWWWqZFmnZGZbmVCdMzvvShfzfGcdcfMSS
+WqbjnmbnjWgmFFgtWVbWZwNTNLjNprNwQLDwrTrHQr
+lwwlcjlzQRBcBccbdLCVnNVWJJzfLndd
+pZDMtZpSDMZpMZMsPtHVNJVfRCRddVndnJLSJd
+mDTZvTqtDDHttRPcqhQlwgGlghbqBh
+DTspTqssqTbdmCMwVmnmlfCD
+PLPWjjrSjvPzqZvjvRqjLtPwnnHCmWVcncMnnwmncHcHll
+RFztFjjqjQFQTbdTbQ
+hTFSVSdhMMVMFjjgbthcbzczcg
+DvwCJVJWWJDRnfmbDmccfmmgfb
+QrJvPGWWnpVMqdZsZpqM
+gRLcHbgnfpgpJjlqqp
+SFwrTHFBqlZtBPZq
+HTzDwmSvCvCmsmmvTSwvFwcfRRNRLcQRWNssNNbRWLWL
+PpMgDMDnsWSnjBQnrjbn
+LFcVVGChCFdhdVFZVpVCdVbvQbRrbvBBbBjQSJZrrJrR
+FNwGNCCFHcVTHcFdHHHTDzMzfsgzwpPWMmPflmtt

2022/4.c

@@ -0,0 +1,90 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct Assignment {
+  char *range;
+  int start;
+  int end;
+};
+
+// Split each line into 2 strings representing the assignment range for each elf
+void parse_assignments(char *assignments, struct Assignment *elf1,
+                       struct Assignment *elf2) {
+
+  elf1->range = strtok(assignments, ",");
+  elf2->range = strtok(NULL, ",");
+}
+
+// Split each assignment range into a start and end
+void parse_sections(struct Assignment *elf) {
+  elf->start = atoi(strtok(elf->range, "-,"));
+  elf->end = atoi(strtok(NULL, "-,"));
+}
+
+// Count the number of assignments that fully contain the other
+void count_subsets(int *count, struct Assignment *elf1,
+                   struct Assignment *elf2) {
+
+  if ((elf1->start >= elf2->start && elf1->end <= elf2->end) ||
+      (elf2->start >= elf1->start && elf2->end <= elf1->end)) {
+    *count += 1;
+  }
+}
+
+// Count the number of assignments with any overlapping sections
+void count_overlaps(int *count, struct Assignment *elf1,
+                    struct Assignment *elf2) {
+
+  if ((elf1->start <= elf2->end && elf1->end >= elf2->start) ||
+      (elf2->start <= elf1->end && elf2->end >= elf1->start)) {
+    *count += 1;
+  }
+}
+
+int main(int argc, char *argv[]) {
+
+  if (argc != 2) {
+    fprintf(stderr, "USAGE: %s input_file\n", argv[0]);
+    return 1;
+  }
+
+  FILE *file = fopen(argv[1], "r");
+  if (!file) {
+    perror("fopen");
+    return 1;
+  }
+
+  int part1_count = 0;
+  int part2_count = 0;
+  char assignments[16] = {0};
+
+  while (fgets(assignments, sizeof assignments / sizeof *assignments, file)) {
+
+    if (strlen(assignments) == 1) {
+      break;
+    }
+
+    struct Assignment elf1;
+    struct Assignment elf2;
+
+    assignments[strlen(assignments) - 1] = '\0';
+
+    // split input into starting and ending points
+    parse_assignments(assignments, &elf1, &elf2);
+    parse_sections(&elf1);
+    parse_sections(&elf2);
+
+    // Part 1 - count sections that fully are fully contained by another
+    count_subsets(&part1_count, &elf1, &elf2);
+
+    // Part 2 - count all overlapping sections
+    count_overlaps(&part2_count, &elf1, &elf2);
+  }
+
+  printf("Part 1 - %d ranges fully contain another\n", part1_count);
+  printf("part 2 - %d assignments overlap\n", part2_count);
+
+  fclose(file);
+  return 0;
+}