Target Sum

题目链接
题目描述

比较直接的想法是通过递归来做
实现代码如下

class Solution {public:    int findTargetSumWays(vector<int>& nums, int S) {        return sumNum(nums,nums.size(),S);    }    int sumNum(vector<int> &nums, int n, int s){        if(n == 1){            int count = 0;            if(nums[0] == s){                count++;            }            if(-nums[0] == s){                count++;            }            return count;        }        return sumNum(nums, n - 1, s - nums[n - 1]) + sumNum(nums, n - 1, s + nums[n - 1]);    }};