56[LeetCode] .Merge Intervals

Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target.

Note:

The solution set must not contain duplicate quadruplets.

Example:

Given array nums = [1, 0, -1, 0, -2, 2], and target = 0.

A solution set is:

[

  [-1,  0, 0, 1],

  [-2, -1, 1, 2],

  [-2,  0, 0, 2]

]

注意sort() 中的cmp()比较函数的定义要放在类外面：

/**

 * Definition for an interval.

 * struct Interval {

 *     int start;

 *     int end;

 *     Interval() : start(0), end(0) {}

 *     Interval(int s, int e) : start(s), end(e) {}

 * };

 */

bool cmp(Interval a,Interval b){return a.start<b.start;}

class Solution {

public:

    vector<Interval> merge(vector<Interval>& ins) {

    if (ins.empty()) return vector<Interval>{};

    vector<Interval> res;

    sort(ins.begin(), ins.end(), cmp);

    res.push_back(ins[]);

    for (int i = ; i < ins.size(); i++) {

        if (res.back().end < ins[i].start) res.push_back(ins[i]);

        else

            res.back().end = max(res.back().end, ins[i].end);

    }

    return res;

    }

};

如在在sort中定义排序方法应该这么写：

vector<Interval> merge(vector<Interval>& ins) {

    if (ins.empty()) return vector<Interval>{};

    vector<Interval> res;

    sort(ins.begin(), ins.end(), [](Interval a, Interval b){return a.start < b.start;});

    res.push_back(ins[]);

    for (int i = ; i < ins.size(); i++) {

        if (res.back().end < ins[i].start) res.push_back(ins[i]);

        else

            res.back().end = max(res.back().end, ins[i].end);

    }

    return res;

}

巴特西

56[LeetCode] .Merge Intervals

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