[Princeton Algorithm I] Programming Assignment 1: Percolation（带权并查集）

题目链接：http://coursera.cs.princeton.edu/algs4/assignments/percolation.html

题意：比较繁琐，就是说从第1行到第n行有没有一个连通块能连起来。复习考研码力变弱了太多，这题调了2h。带权并查集，行号越小权值越高就行了。

使用方法：windows下编译运行，按住一个键不放。

  1 #include <stdio.h>
  2 #include <string.h>
  3 #include <stdlib.h>
  4 #include <conio.h>
  5 #include <time.h>
  6 
  7 const int dx[5] = {0, 0, 1, -1};
  8 const int dy[5] = {1, -1, 0, 0};
  9 
 10 static struct RandomGen {
 11     RandomGen() { srand((int)time(NULL)); }
 12     static int getRandom() { return (int)rand()*(int)rand()+(int)rand(); }
 13 }RandomGen;
 14 
 15 typedef struct Percolation {
 16     int* pre;
 17     int** _G;
 18     int n, m;
 19 
 20     Percolation() {}
 21     Percolation(int _n, int _m) : n(_n), m(_m) {
 22         int _size = _n * _m;
 23         pre = (int*)malloc(_size*sizeof(int));
 24         _G = (int**)malloc(_n*sizeof(int*));
 25         for(int i = 0; i < _size; i++) {
 26             pre[i] = i;
 27         }
 28         for(int i = 0; i < n; i++) {
 29             _G[i] = (int*)malloc(_m*sizeof(int));
 30             for(int j = 0; j < m; j++) {
 31                 _G[i][j] = 0;
 32             }
 33         }
 34     }
 35 
 36     int find(int x) {
 37         return x == pre[x] ? x : pre[x] = find(pre[x]);
 38     }
 39 
 40     void unite(int x, int y) {
 41         x = find(x), y = find(y);
 42         if(x > y) pre[x] = y;
 43         else pre[y] = x;
 44     }
 45 
 46     inline int getId(int x, int y) { return x * m + y; }
 47     inline int ok(int x, int y) { return x >= 0 && y >= 0 && x < n && y < m; }
 48 
 49     inline void update(int x, int y) {
 50         _G[x][y] = 1;
 51         for(int i = 0; i < 4; i++) {
 52             int xx = x + dx[i], yy = y + dy[i];
 53             if(!ok(xx, yy) || !_G[xx][yy]) continue;
 54             unite(getId(x, y), getId(xx, yy));
 55         }
 56     }
 57 }Percolation;
 58 
 59 typedef struct PrintControl {
 60     Percolation* perc;
 61 
 62     PrintControl() {}
 63     PrintControl(Percolation* _p) : perc(_p) {}
 64     
 65     inline char sign(int x, int y) {
 66         int id = perc->getId(x, y);
 67         if(perc->_G[x][y]) {
 68             if(perc->find(id) / perc->m == 0) return 'O';
 69             else return '.';
 70         }
 71         else return 'X';
 72     }
 73 
 74     void Print() {
 75         system("cls");
 76         for(int i = 0; i < perc->n; i++) {
 77             for(int j = 0; j < perc->m; j++) {
 78                 printf("%c", sign(i, j));
 79             }
 80             printf("\n");
 81         }
 82         printf("\n");
 83     }
 84 }PrintControl;
 85 
 86 typedef struct Simulator {
 87     int n, m, initSize;
 88     Percolation perc;
 89     PrintControl pc;
 90 
 91     Simulator() {}
 92     Simulator(int _n, int _m, int _i) : n(_n), m(_m), initSize(_i) {
 93         perc = Percolation(n, m);
 94         pc = PrintControl(&perc);
 95         while(_i--) update();
 96     }
 97 
 98     void update() {
 99         int x = RandomGen::getRandom() % n,
100               y = RandomGen::getRandom() % m;
101         perc.update(x, y);
102     }
103     
104     void Semaphore() {
105         update();
106         pc.Print();
107         getch();
108     }
109 }Simulator;
110 
111 signed main() {
112     // freopen("out", "w", stdout);
113     Simulator sim(20, 20, 5);
114     sim.pc.Print();
115     while(1) {
116         sim.Semaphore();
117     }
118     return 0;
119 }

 

posted @ 2017-12-27 20:27  Kirai  阅读(405)  评论(0)  编辑  收藏  举报