Given a list of 24-hour clock time points in "Hour:Minutes" format, find the minimum minutes difference between any two time points in the list.
Example 1:
Input: ["23:59","00:00"] Output: 1
Note:
The number of time points in the given list is at least 2 and won't exceed 20000The input time is legal and ranges from 00:00 to 23:59.题目链接：https://leetcode.com/problems/minimum-time-difference/#/description
题目大意：给定一个24小时制的一组时间，求出任意两个时间的最小间隔。
思路：将24小时每一分钟映射到一个长度为24*60的hash表中，时间复杂度为O（N）。
参考代码：
class Solution { public: int findMinDifference(vector<string>& timePoints) { int n = timePoints.size() ; if ( n < 2 ) return 0 ; int ans = INT_MAX , N = 24 * 60 , pre = 0 , maxer = 0 ; vector <bool> has ( N , false ) ; for ( int i = 0 ; i < n ; i ++ ) { string s = timePoints[i] ; int k = s.find ( ':' ) ; int h = atoi ( s.substr ( 0 , k ).c_str() ) , m = atoi ( s.substr ( k + 1 ).c_str() ) ; int index = h * 60 + m ; if ( index == N ) index = 0 ; if ( has[index] ) return 0 ; has[index] = true ; } bool judge = true ; for ( int i = 0 ; i < N ; i ++ ) { if ( has[i] ) { if ( judge ) { pre = i ; judge = false ; maxer = i + N ; } else { ans = min ( ans , i - pre ) ; pre = i ; } } } ans = min ( ans , maxer - pre ) ; return ans ; } };
