leetcode--Merge Intervals

1.题目描述

Given a collection of intervals, merge all overlapping intervals.

For example,

Given [1,3],[2,6],[8,10],[15,18],

return [1,6],[8,10],[15,18].

2.解法分析

题目很简单。只是自定义的排序仿函数要放在solution类外面，否则会出现如下错误：

Line 23: no matching function for call to 'sort(std::vector<Interval>::iterator, std::vector<Interval>::iterator, <unresolved overloaded function type>)'

代码如下：

/**

 * 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 lc(const Interval &a,const Interval &b)

    return a.start<b.start;

class Solution {

public:

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

        // Start typing your C/C++ solution below

        // DO NOT write int main() function

        vector<Interval>result;

        if(intervals.empty())return result;

        std::sort(intervals.begin(),intervals.end(),lc);

        Interval cur=intervals[0];

        int len=intervals.size();

        if(len==1)return intervals;

        int i=1;

        while(i<len)

            if(cur.end>=intervals[i].start)

                cur.end=max(intervals[i].end,cur.end);

            else

                result.push_back(cur);

                cur=intervals[i];

            i++;

        if(result.empty()||result.back().end<cur.start)result.push_back(cur);

        return result;

};

leetcode--Merge Intervals

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