贪心 CodeForces 124B Permutations

 

题目传送门

 1 /*  2  贪心：全排列函数使用，更新最值  3 */  4 #include <cstdio>  5 #include <algorithm>  6 #include <cstring>  7 #include <cmath>  8 #include <string>  9 #include <vector> 10 #include <map> 11 #include <set> 12 #include <iostream> 13 #include <queue> 14 using namespace std; 15 16 typedef long long ll; 17 const int MAXN = 20; 18 const int INF = 0x3f3f3f3f; 19 int b[MAXN]; 20 char a[MAXN][MAXN]; 21 22 int main(void) //CodeForces 124B Permutations 23 { 24 // freopen ("A.in", "r", stdin); 25 26 int n, k; 27 while (scanf ("%d%d", &n, &k) == 2) 28  { 29 for (int i=1; i<=n; ++i) 30  { 31 scanf ("%s", a[i] + 1); 32  } 33 for (int i=1; i<=k; ++i) b[i] = i; 34 35 ll ans = INF; 36 do 37  { 38 ll mx = 0, mn = INF; ll sum = 0; 39 for (int i=1; i<=n; ++i) 40  { 41 sum = 0; 42 for (int j=1; j<=k; ++j) 43  { 44 sum = sum * 10 + (a[i][b[j]] - '0'); 45  } 46 if (sum > mx) mx = sum; 47 if (sum < mn) mn = sum; 48  } 49 ans = min (ans, mx - mn); 50 }while (next_permutation (b+1, b+1+k)); 51 52 printf ("%I64d\n", ans); 53  } 54 55 return 0; 56 }