// 877. Stone Game #include "leetcode.h" /* * alice and bob play a game with piles of stones. there are an even number of * piles arranged in a row, and each pile has a positive integer number of * stones 'piles[i]'. the objective of the game is to end with the most stones. * the total number of stones across all piles isodd, so there are no ties. * alice and bob take turns, with alice starting first. each turn a player takes * the entire pile of stones either from the beginning or from the end of the * row. this continues until there are no more piles left, at which point the * person with the most stones wins. assuming alice and bob play optimally, * return 'true' if alice wins the game, or 'false' if bob wins. */ bool stoneGame(int *piles, int piles_size) { int **dp = (int **)malloc(sizeof(int *) * piles_size); int **sum = (int **)malloc(sizeof(int *) * piles_size); for (int i = 0; i < piles_size; i++) { dp[i] = (int *)malloc(sizeof(int) * piles_size); sum[i] = (int *)malloc(sizeof(int) * piles_size); for (int j = 0; j < piles_size; j++) if (i == j) { dp[i][j] = piles[i]; sum[i][j] = piles[i]; } } for (int l = 2; l <= piles_size; ++l) for (int i = 0; i <= piles_size; ++i) { int j = i + l - 1; sum[i][j] = sum[i][j - 1] + piles[j]; dp[i][j] = sum[i][j] - fmin(dp[i][j - 1], dp[i + 1][j]); } bool ans = (dp[0][piles_size - 1] * 2 > sum[0][piles_size - 1]); for (int i = 0; i < piles_size; i++) free(dp[i]), free(sum[i]); free(dp), free(sum); return ans; } int main() { int p1[] = {5, 3, 4, 5}, p2[] = {3, 7, 2, 3}; printf("%d\n", stoneGame(p1, ARRAY_SIZE(p1))); // expect: 1 printf("%d\n", stoneGame(p2, ARRAY_SIZE(p2))); // expect: 1 }