【LeetCode热题100（56/100）】组合总和

题目地址： 链接

思路： 递归回溯

/**
 * @param {number[]} candidates
 * @param {number} target
 * @return {number[][]}
 */
var combinationSum = function(candidates, target) {
    let n = candidates.length
    let ans = [];
    const dfs = (idx, sum, arr) => {
        if(sum > target) return;
        if(sum === target) {
            ans.push(arr);
            return;
        }

        for(let i = idx; i < n; i ++) {
            dfs(i, sum + candidates[i], [...arr, candidates[i]]);
        }
    }

    dfs(0, 0, []);
    return ans;
};