Submission #328911

#	Time	Username	Problem	Language	Result	Execution time	Memory
328911		sofapuden	Linear Garden (IOI08_linear_garden)	C++14	100 / 100	114 ms	2440 KiB

linear_garden

#include <bits/stdc++.h>
#define int ll

using namespace std;

typedef long long int;

int M;

int po(int a, int b){
int _a = a, _b = b;
int ret = 1;
while(_b){
if(_b&1){ret*=_a;ret%=M;}
_a*=_a;
_a%=M;
_b>>=1;
}
return ret;
}

signed main(){
ios_base::sync_with_stdio(0); cin.tie(0);
int n; cin >> n >> M;

string s; cin >> s;

int l = 0, r = 0, ans = 0, now = 0;
for(int i = 0; i < n; ++i){
if(s[i] == 'L'){now++, r = max(r,now);continue;}
int rb = max(r,now+1);
int rb2 = n-i-1;
if(rb-l == 1){
ans+=po(2,rb2>>1);
ans+=po(2,(rb2+1)>>1);
ans--;
ans+=M;
ans%=M;
}
else if(rb-l == 2){
if(now+2==rb)ans+=po(2,(rb2+1)>>1);
else ans+=po(2,rb2>>1);
}
now--, l = min(l,now);
}
cout << (ans+1)%M << "\n";
}

• Subtask 1: 2 / 2
• Subtask 2: 2 / 2
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• Subtask 23: 5 / 5