【next_permutation暴力+剪枝】2018 hdu多校第五場 1002 Beautiful Now
Beautiful Now
Time Limit: 5000/2500 MS (Java/Others) Memory Limit: 262144/262144 K (Java/Others)
Total Submission(s): 626 Accepted Submission(s): 196
Problem Description
Anton has a positive integer n, however, it quite looks like a mess, so he wants to make it beautiful after k swaps of digits.
Let the decimal representation of n as (x1x2⋯xm)10 satisfying that 1≤x1≤9, 0≤xi≤9 (2≤i≤m), which means n=∑mi=1xi10m−i. In each swap, Anton can select two digits xi and xj (1≤i≤j≤m) and then swap them if the integer after this swap has no leading zero.
Could you please tell him the minimum integer and the maximum integer he can obtain after k swaps?
Input
The first line contains one integer T, indicating the number of test cases.
Each of the following T lines describes a test case and contains two space-separated integers n and k.
1≤T≤100, 1≤n,k≤109.
Output
For each test case, print in one line the minimum integer and the maximum integer which are separated by one space.
Sample Input
5
12 1
213 2
998244353 1
998244353 2
998244353 3
Sample Output
12 21
123 321
298944353 998544323
238944359 998544332
233944859 998544332
Source
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#include <bits/stdc++.h> using namespace std; char a[20]; int c[20],q[20],q1[20],p[20],k,len; int minn,maxx; void update() { if(c[p[1]]==0) return; //第一位數字是0,不符合規則 for(int i=1;i<=len;i++) q[i]=p[i]; //q陣列內儲存全排列後的位置 int k1=0,s=0; for(int i=1;i<=len;i++) { s=s*10+c[p[i]]; if(q[i]!=i) //如果當前位數字更改了 { for(int j=i+1;j<=len;j++) { if(q[j]==i) { swap(q[i],q[j]); k1++; if(k1>k) return; break; } } } } if(k1>k) return;//轉換了超過k次,就不行,可以的話,再看 maxx=max(maxx,s); minn=min(minn,s); } int main() { int T; scanf("%d",&T); while(T--) { memset(q,0,sizeof(q)); memset(q1,0,sizeof(q1)); scanf("%s%d",a+1,&k); len=strlen(a+1); for(int i=1;i<=len;i++) { c[i]=a[i]-'0'; q[c[i]]++; q1[c[i]]++; } if(k>=len-1) //直接得到最大最小!!!不加等於就TLE { for(int i=1;i<=9;i++) { if(q[i]) { printf("%d",i); q[i]--; break; } } for(int i=0;i<=9;i++) { while(q[i]) { printf("%d",i); q[i]--; } } printf(" "); for(int i=9;i>=0;i--) { while(q1[i]) { printf("%d",i); q1[i]--; } } printf("\n"); continue; } for(int i=1;i<=len;i++) p[i]=i; //每一位數字原來儲存在哪裡 minn=2e9,maxx=-1; do { update(); } while(next_permutation(p+1,p+len+1)) ;//全排列 printf("%d %d\n",minn,maxx); } return 0; }