[BOJ] 1039 교환

Time Lapse :47min 34sec

1039.cpp

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#include <iostream>
#include <algorithm>
#include <memory.h>
using namespace std;
int n, k, ans;
bool v[1000000][10];
int isUppercase(string& str) {
for(int i = 0; i < str.length(); i++) {
for(int j = i + 1; j < str.length(); j++)
if(str[i] < str[j])
return i;
}
return -1;
}
void dfs(string str, int d) {
int num = atoi(str.c_str());
if(d == k) {
ans = max(ans, num);
return ;
}
if(v[num][d]) return;
v[num][d] = true;
int start = isUppercase(str);
string nString;
if(start == -1) {
for(int i = 1; i < str.length(); i++)
if(str[i] == str[i-1]) {
ans = max(ans, num);
return ;
}
nString = str;
swap(nString[nString.length()-1], nString[nString.length()-2]);
dfs(nString, d+1);
return;
}
for(int i = start; i < str.length(); i++)
for(int j = i + 1; j < str.length(); j++) {
nString = str;
swap(nString[i], nString[j]);
dfs(nString, d + 1);
}
}
int main(){
scanf("%d %d",&n, &k);
if(n <= 10 || (n < 100 && !(n % 10))) {
printf("-1");
exit(0);
}
dfs(to_string(n),0);
cout<<ans;
}
Author: Song Hayoung
Link: https://songhayoung.github.io/2020/09/09/PS/BOJ/1039/
Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 4.0 unless stating additionally.