20180613更新 leetcode刷题

最近就是忙工作项目工作间隙就刷了刷LEETCODE 所以没啥更新

  1 // 1111111.cpp: 定义控制台应用程序的入口点。
  2 //
  3 
  4 #include "stdafx.h"
  5 #include <vector>
  6 #include <queue>
  7 
  8 using namespace std;
  9 
 10 bool canFinish1(int numCourses, vector<vector<int>>& prerequisites) {
 11     vector<vector<int> > graph(numCourses, vector<int>(0));
 12     vector<int> in(numCourses, 0);
 13     for (auto a : prerequisites) {
 14         graph[a[1]].push_back(a[0]);
 15         ++in[a[0]];
 16     }
 17     queue<int> q;
 18     for (int i = 0; i < numCourses; ++i) {
 19         if (in[i] == 0) q.push(i);
 20     }
 21     while (!q.empty()) {
 22         int t = q.front();
 23         q.pop();
 24         for (auto a : graph[t]) {
 25             --in[a];
 26             if (in[a] == 0) q.push(a);
 27         }
 28     }
 29     for (int i = 0; i < numCourses; ++i) {
 30         if (in[i] != 0) return false;
 31     }
 32     return true;
 33 }
 34 
 35 //==========================================================================
 36 
 37 bool canFinishDFS(vector<vector<int> > &graph, vector<int> &visit, int i) {
 38     if (visit[i] == -1) return false;
 39     if (visit[i] == 1) return true;
 40     visit[i] = -1;
 41     for (auto a : graph[i]) {
 42         if (!canFinishDFS(graph, visit, a)) return false;
 43     }
 44     visit[i] = 1;
 45     return true;
 46 }
 47 
 48 bool canFinish2(int numCourses, vector<vector<int> >& prerequisites) {
 49     vector<vector<int> > graph(numCourses, vector<int>(0));
 50     vector<int> visit(numCourses, 0);
 51     for (auto a : prerequisites) {
 52         graph[a[1]].push_back(a[0]);
 53     }
 54     for (int i = 0; i < numCourses; ++i) {
 55         if (!canFinishDFS(graph, visit, i)) return false;
 56     }
 57     return true;
 58 }
 59 
 60 
 61 int main()
 62 {
 63     //测试数据
 64     {
 65         int i = 2;
 66         vector<vector<int> > v;
 67         v.push_back(std::vector<int>{0, 1});
 68         v.push_back(std::vector<int>{1 ,0});
 69         canFinish1(i , v);
 70     }
 71     //{
 72     //    int i = 2;
 73     //    vector<vector<int> > v;
 74     //    v.push_back(std::vector<int>{1, 0});
 75     //    v.push_back(std::vector<int>{0, 1});
 76     //}
 77     //{
 78     //    int i = 2;
 79     //    vector<vector<int> > v;
 80     //    v.push_back(std::vector<int>{1, 0});
 81     //}
 82     //{
 83     //    int i = 3;
 84     //    vector<vector<int> > v;
 85     //    v.push_back(std::vector<int>{1, 0});
 86     //    v.push_back(std::vector<int>{2, 0});
 87     //}
 88 
 89 //    {
 90 //        int i = 3;
 91 //        vector<vector<int> > v;
 92 //        v.push_back(std::vector<int>{1, 0});
 93 //        v.push_back(std::vector<int>{2, 0});
 94 //    }
 95 //
 96 //    {
 97 //        int i = 3;
 98 //        vector<vector<int> > v;
 99 //        v.push_back(std::vector<int>{0, 1});
100 //        v.push_back(std::vector<int>{1, 2});
101 //    }
102 //
103 //    {
104 //        int i = 4;
105 //        vector<vector<int> > v;
106 //        v.push_back(std::vector<int>{0, 1});
107 //        v.push_back(std::vector<int>{1, 2});
108 //        v.push_back(std::vector<int>{2, 0});
109 //        v.push_back(std::vector<int>{1, 3});
110 //    }
111 //
112 //    {
113 //        int i = 4;
114 //        vector<vector<int> > v;
115 //        v.push_back(std::vector<int>{0, 1});
116 //        v.push_back(std::vector<int>{1, 2});
117 //        v.push_back(std::vector<int>{1, 3});
118 //    }
119 
120 
121 
122 
123     return 0;
124 }