#include<bits/stdc++.h>
#define fi first
#define se second
#define int long long
using namespace std;
using ll = long long;
using ii = pair<int, int>;
using aa = array<int,3>;
const int N = 205;
const int INF = 1e9;
int dp[N][N][N][3];
int nxt[N][3];
int pre[N][3];
int pos[N][3];
void solve(int r,int b,int y,int i) {
int cur[3]={r,b,y};
for(int j=0;j<3;j++) {
if(cur[j]==0) continue;
int pos0=pos[cur[j]][j];
int j1=(j+1)%3,j2=(j+2)%3;
int pos1=pos[cur[j1]][j1];
int pos2=pos[cur[j2]][j2];
int t=pos0+max(0LL,cur[j1]-pre[pos0][j1])+max(0LL,cur[j2]-pre[pos0][j2])-i;
int nw[3]={cur[0],cur[1],cur[2]};
nw[j]--;
int mi=min(dp[nw[0]][nw[1]][nw[2]][j1],dp[nw[0]][nw[1]][nw[2]][j2]);
dp[cur[0]][cur[1]][cur[2]][j]=mi+t;
}
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
cin >> n;
for(int i=1;i<=n;i++) {
char x;
cin >> x;
int t=0;
if(x=='G') t=1;
if(x=='Y') t=2;
pre[i][t]++;
for(int j=0;j<3;j++) {
pre[i][j]+=pre[i-1][j];
if(pre[i][j]>(n+1)/2) {
cout << -1;
return 0;
}
}
pos[pre[i][t]][t]=i;
}
for(int i=n;i>0;i--) {
for(int j=0;j<3;j++) {
nxt[i][j]=nxt[i+1][j];
if(pre[i][j]-pre[i-1][j]==1) nxt[i][j]=i;
}
}
for(int i=0;i<=pre[n][0];i++) {
for(int j=0;j<=pre[n][1];j++) {
for(int k=0;k<=pre[n][2];k++) {
for(int l=0;l<3;l++) dp[i][j][k][l]=1e9;
}
}
}
for(int i=0;i<3;i++) dp[0][0][0][i]=0;
for(int i=1;i<=n;i++) {
for(int r=0;r<=pre[n][0];r++) {
for(int b=0;b<=pre[n][1];b++) {
int y=i-r-b;
if(y<0) break;
if(y>pre[n][2]) continue;
if(max({y,r,b})>(i+1)/2) {
continue;
}
solve(r,b,y,i);
//cout << r << ' ' << b << ' ' << y << ' ' << min({dp[r][b][y][0],dp[r][b][y][1],dp[r][b][y][2]}) << endl;;
}
}
}
int ans=1e9;
for(int i=0;i<3;i++) {
ans=min(ans,dp[pre[n][0]][pre[n][1]][pre[n][2]][i]);
}
cout << ans;
return 0;
}
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |