题意：给你n条线段，问你这些线段可以组成的矩形和最大是多少。每条线段可以-1,。
解题思路：贪心.
解题代码：
1 // File Name: d.cpp 2 // Author: darkdream 3 // Created Time: 2015年03月27日 星期五 16时05分31秒 4 5 #include<vector> 6 #include<list> 7 #include<map> 8 #include<set> 9 #include<deque> 10 #include<stack> 11 #include<bitset> 12 #include<algorithm> 13 #include<functional> 14 #include<numeric> 15 #include<utility> 16 #include<cstdio> 17 #include<cmath> 18 #include<cstdlib> 19 #include<ctime> 20 #include<queue> 21 #define LL long long 22 23 using namespace std; 24 int n ,m ; 25 char mp[2005][2005]; 26 bool vis[2005][2005]; 27 struct node{ 28 int x, y; 29 node(){} 30 node(int _x, int _y) 31 { 32 x = _x; 33 y = _y ; 34 } 35 }tmp; 36 int lx, ly ,rx,ry; 37 int xadd[] = {0,0,1,-1}; 38 int yadd[] = {1,-1,0,0}; 39 queue<node>qu; 40 void bfs(int x,int y) 41 { 42 qu.push(node(x,y)); 43 int tx,ty; 44 while(!qu.empty()) 45 { 46 tmp = qu.front(); 47 qu.pop(); 48 if(mp[tmp.x][tmp.y] != '.') 49 continue; 50 if(mp[tmp.x-1][tmp.y] == '.' && mp[tmp.x][tmp.y+1] =='.' && mp[tmp.x-1][tmp.y+1] == '*') 51 { 52 tx = tmp.x -1; 53 ty = tmp.y +1; 54 mp[tx][ty] = '.'; 55 qu.push(node(tx,ty)); 56 for(int i = 0 ;i <= 3 ;i ++) 57 qu.push(node(tx+xadd[i],ty+yadd[i])) ; 58 } 59 if(mp[tmp.x-1][tmp.y] == '.' && mp[tmp.x][tmp.y-1] =='.' && mp[tmp.x-1][tmp.y-1] == '*') 60 { 61 tx = tmp.x -1; 62 ty = tmp.y -1; 63 mp[tx][ty] = '.'; 64 qu.push(node(tx,ty)); 65 for(int i = 0 ;i <= 3 ;i ++) 66 qu.push(node(tx+xadd[i],ty+yadd[i])) ; 67 } 68 if(mp[tmp.x+1][tmp.y] == '.' && mp[tmp.x][tmp.y+1] =='.' && mp[tmp.x+1][tmp.y+1] == '*') 69 { 70 tx = tmp.x +1; 71 ty = tmp.y +1; 72 mp[tx][ty] = '.'; 73 qu.push(node(tx,ty)); 74 for(int i = 0 ;i <= 3 ;i ++) 75 qu.push(node(tx+xadd[i],ty+yadd[i])) ; 76 } 77 if(mp[tmp.x+1][tmp.y] == '.' && mp[tmp.x][tmp.y-1] =='.' && mp[tmp.x+1][tmp.y-1] == '*') 78 { 79 tx = tmp.x +1; 80 ty = tmp.y -1; 81 mp[tx][ty] = '.'; 82 qu.push(node(tx,ty)); 83 for(int i = 0 ;i <= 3 ;i ++) 84 qu.push(node(tx+xadd[i],ty+yadd[i])) ; 85 } 86 } 87 } 88 int main(){ 89 scanf("%d %d",&n,&m); 90 for(int i = 1;i <= n;i ++) 91 { 92 scanf("%s",&mp[i][1]); 93 } 94 for(int i = 1 ;i <= n;i ++) 95 { 96 for(int j = 1;j <= m;j ++) 97 { 98 if( mp[i][j] == '.') 99 { 100 bfs(i,j); 101 } 102 } 103 } 104 for(int i = 1;i <= n;i ++) 105 puts(&mp[i][1]); 106 return 0; 107 }