Implement dynamic programming solution for tribonacci and fix index calculation in sequence matching

src/1137.c

@@ -4,4 +4,14 @@
 #include <solution/1137.h>
 int tribonacci(int n)
 {
+    int dp[n + 1];
+    dp[0] = 0;
+    if (n >= 1)
+        dp[1] = 1;
+    if (n >= 2)
+        dp[2] = 1;
+    for (int i = 3; i <= n; i++)
+        dp[i] = dp[i - 3] + dp[i - 2] + dp[i - 1];
+
+    return dp[n];
 }