combination-sum-ii.js

/**
 * @param {number[]} candidates
 * @param {number} target
 * @return {number[][]}
 */

var combinationSum2 = function(candidates, target) {

    var res = [];
    var len = candidates.length;
    candidates.sort((a, b) => (a - b));
    dfs(res, [], 0, len, candidates, target);
    return res;
};

var dfs = function (res, stack, index, len, candidates, target) {
  
    var tmp = null;
    if (target < 0) 
        return;
    if (target === 0) 
        return res.push(stack);
    for (var i = index; i < len; i++) {
        if (candidates[i] > target) 
            break;
        if (i > index && candidates[i] === candidates[i - 1]) 
            continue;
        tmp = Array.from(stack);
        tmp.push(candidates[i]);
        dfs(res, tmp, i + 1, len, candidates, target - candidates[i]);
  }
    
};