Create: 0332-reconstruct-itinerary.c

Author: mdmzfzl

Diff for: c/0332-reconstruct-itinerary.c

@@ -0,0 +1,51 @@
+int cmp(const void *a, const void *b) {
+    const char **s1 = *(const char ***)a, **s2 = *(const char ***)b;
+    int c = strcmp(s1[0], s2[0]);
+    if (c) return c;
+    return strcmp(s1[1], s2[1]);
+}
+
+int dfs(int *v, char ***tickets, int n, char **p, int last, int d) {
+    int i;
+    
+    if (d == n) {
+        p[n] = tickets[last][1];
+        return 1;
+    }
+    
+    for (i = 0; i < n; i++) {
+        if (!v[i] && !strcmp(tickets[last][1], tickets[i][0])) {
+            v[i] = 1;
+            p[d] = tickets[i][0];
+            if (dfs(v, tickets, n, p, i, d + 1)) return 1;
+            v[i] = 0;
+        }
+    }
+    
+    return 0;
+}
+
+char** findItinerary(char*** tickets, int ticketsRowSize, int ticketsColSize, int* returnSize) {
+    int *v, i, done;
+    char **p;
+    
+    qsort(tickets, ticketsRowSize, sizeof(char **), cmp);
+    
+    p = (char **)malloc((ticketsRowSize + 1) * sizeof(char *));
+    v = (int *)calloc(ticketsRowSize, sizeof(int));
+    
+    done = 0;
+    for (i = 0; !done && i < ticketsRowSize; i++) {
+        if (!strcmp(tickets[i][0], "JFK")) {
+            v[i] = 1;
+            p[0] = tickets[i][0];
+            done = dfs(v, tickets, ticketsRowSize, p, i, 1);
+            v[i] = 0;
+        }
+    }
+    
+    *returnSize = ticketsRowSize + 1;
+    free(v);
+    
+    return p;
+}