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Diffstat (limited to 'stone_game2.cpp')
-rw-r--r-- | stone_game2.cpp | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/stone_game2.cpp b/stone_game2.cpp new file mode 100644 index 0000000..808546f --- /dev/null +++ b/stone_game2.cpp @@ -0,0 +1,39 @@ +// 1140. Stone Game II +#include "leetcode.h" + +/* + * alice and bob continue their games with piles of stones. there are a 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. + * alice and bob take turns, with alice starting first. initiall, 'M = 1'. on + * each player's turn, that player can take all the stones on the 'X' remaining + * piles, where '1 <= X <= 2M'. then, we set 'M = max(M, X)'. the game continues + * until all the stones have been take. assuming alice and bob play optimally, + * return maximum stones alice can get. + */ + +class Solution { +public: + int stoneGameII(vector<int> &piles) { + int n = piles.size(); + vvd(int) dp(n + 1, vector<int>(n + 1, 0)); + vector<int> sum(n + 1, 0); + for (int i = n - 1; i >= 0; i--) + sum[i] = sum[i + 1] + piles[i]; + for (int i = 0; i <= n; i++) + dp[i][n] = sum[i]; + for (int i = n - 1; i >= 0; i--) + for (int j = n - 1; j >= 1; j--) + for (int k = 1; k <= 2 * j && i + j <= n; j++) + dp[i][j] = max(dp[i][j], sum[i] - dp[i + k][max(j, k)]); + return dp[0][1]; + } +}; + +int main() { + Solution obj; + vector<int> p1 = {2, 7, 9, 4, 4}; + vector<int> p2 = {1, 2, 3, 4, 5, 100}; + printf("%d\n", obj.stoneGameII(p1)); // expect: 10 + printf("%d\n", obj.stoneGameII(p2)); // expect: 104 +} |