codeforces 816 C. Karen and Game(模拟+思维)
题目链接:http://codeforces.com/contest/816/problem/C
题意:给出一个矩阵,问能否从都是0的情况下只将一整行+1或者一整列+1变形过来,如果可以输出需要步数最小的情况。不能输出-1
题解:就是一道模拟题,然后关于最小的只要考虑一种情况,就是当前行可以消除,也可以消除全部列的时候要考虑要删行还是删列,这个取决于n于m的大小
#include <iostream> #include <cstring> #include <cstdio> using namespace std; const int Max_Size = 5e2 + 10; int a[Max_Size][Max_Size] , Minrow[Max_Size] , Mincol[Max_Size]; struct TnT { string pos; int num; }T[Max_Size * Max_Size]; int main() { int n , m; cin >> n >> m; for(int i = 1 ; i <= n ; i++) { for(int j = 1 ; j <= m ; j++) { cin >> a[i][j]; } } memset(Minrow , 0 , sizeof(Minrow)); memset(Mincol , 0 , sizeof(Mincol)); for(int i = 1 ; i <= n ; i++) { int Min = Max_Size; for(int j = 1 ; j <= m ; j++) { Min = min(Min , a[i][j]); } Minrow[i] = Min; } for(int i = 1 ; i <= m ; i++) { int Min = Max_Size; for(int j = 1 ; j <= n ; j++) { Min = min(Min , a[j][i]); } Mincol[i] = Min; } int ans = 0; for(int i = 1 ; i <= n ; i++) { if(m > n) { for(int j = 1 ; j <= m ; j++) { a[i][j] -= Minrow[i]; Mincol[j] = min(Mincol[j] , a[i][j]); } for(int j = 1 ; j <= Minrow[i] ; j++) { T[ans].pos = "row"; T[ans].num = i; ans++; } Minrow[i] = 0; } } for(int i = 1 ; i <= m ; i++) { if(m <= n) { for(int j = 1 ; j <= n ; j++) { a[j][i] -= Mincol[i]; Minrow[j] = min(Minrow[j] , a[j][i]); } for(int j = 1 ; j <= Mincol[i] ; j++) { T[ans].pos = "col"; T[ans].num = i; ans++; } Mincol[i] = 0; } } for(int i = 1 ; i <= n ; i++) { for(int j = 1 ; j <= m ; j++) { a[i][j] -= Minrow[i]; Mincol[j] = min(Mincol[j] , a[i][j]); } for(int j = 1 ; j <= Minrow[i] ; j++) { T[ans].pos = "row"; T[ans].num = i; ans++; } Minrow[i] = 0; } for(int i = 1 ; i <= m ; i++) { for(int j = 1 ; j <= n ; j++) { a[j][i] -= Mincol[i]; Minrow[j] = min(Minrow[j] , a[j][i]); } for(int j = 1 ; j <= Mincol[i] ; j++) { T[ans].pos = "col"; T[ans].num = i; ans++; } Mincol[i] = 0; } int flag = 0; for(int i = 1 ; i <= n ; i++) { for(int j = 1 ; j <= m ; j++) { if(a[i][j]) flag = 1; } } if(!flag) { cout << ans << endl; for(int i = 0 ; i < ans ; i++) cout << T[i].pos << ' ' << T[i].num << endl; } else cout << -1 << endl; return 0; }