leetcode 486. Predict the Winner
class Solution {
public:
bool predictTheWinner(vector<int>& nums) {
int m = nums.size();
// f[i][j]表示(i,j)區間上，先手能超過後手多少分
std::vector<std::vector<int>> f(m, std::vector<int>(m));
for (int i = 0; i < m; i++) f[i][i] = nums[i];
for (int len = 2; len <= m; len++)
for (int i = 0; i + len - 1 < m; i++) {
int j = i + len - 1;
f[i][j] = max(nums[i] - f[i + 1][j], nums[j] - f[i][j - 1]);
}
return f[0][m - 1] >= 0;
}
};可以記錄每個狀態是怎麼轉移過來的，然後reverse一下，就得到最優方案了