findTargetSumWays.cpp

class Solution {
public:
    int findTargetSumWays(vector<int>& nums, int target) {
        int sum = std::accumulate(nums.begin(), nums.end(), 0), neg = sum - target;
        if (neg < 0 || neg % 2 != 0) return 0;
        int n = nums.size();
        neg /= 2;
        vector<vector<int> > dp(n + 1, vector<int>(neg + 1, 0));
        dp[0][0] = 1;
        for (int i = 1; i <= n; i++) {
            int num = nums[i - 1];
            for (int j = 0; j <= neg; j++) {
                dp[i][j] = dp[i - 1][j];
                if (j >= num) {
                    dp[i][j] += dp[i - 1][j - num];
                }
            }
        }
        return dp[n][neg];
    }
};

// 作者：LeetCode-Solution
// 链接：https://leetcode-cn.com/problems/target-sum/solution/mu-biao-he-by-leetcode-solution-o0cp/
// 来源：力扣（LeetCode）
// 著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。