Submission #621022

#	Time	Username	Problem	Language	Result	Execution time	Memory
621022		amunduzbaev	Mutating DNA (IOI21_dna)	C++17	100 / 100	41 ms	5436 KiB

dna

#include "dna.h"
#ifndef EVAL
#include "grader.cpp"
#endif
#include "bits/stdc++.h"
using namespace std;

#define ar array

const int N = 1e5 + 5;
ar<int, 4> pref[N];

void init(string a, string b) {
	int n = a.size();
	for(int i=0;i<n;i++){
		if(i) pref[i] = pref[i-1];
		if(a[i] == b[i]) pref[i][3]++;
		else {
			if(a[i] == 'A' && b[i] == 'T') pref[i][0]++;
			if(a[i] == 'T' && b[i] == 'C') pref[i][1]++;
			if(a[i] == 'C' && b[i] == 'A') pref[i][2]++;
			swap(a[i], b[i]);
			if(a[i] == 'A' && b[i] == 'T') pref[i][0]--;
			if(a[i] == 'T' && b[i] == 'C') pref[i][1]--;
			if(a[i] == 'C' && b[i] == 'A') pref[i][2]--;
		}
	}
}

int get_distance(int x, int y) {
	ar<int, 4> a = pref[y];
	if(x){
		for(int t=0;t<4;t++) a[t] -= pref[x-1][t];
	}
	
	if(a[0] == a[1] && a[1] == a[2]){
		//~ cout<<a[0]<<" "<<a[1]<<" "<<a[2]<<"\n";
		int res = y - x + 1 - a[3];
		a[0] = abs(a[0]);
		assert((res - a[0] * 3) % 2 == 0);
		res = (res - a[0] * 3) / 2 + a[0] * 2;
		return res;
	}
	return -1;
}

• Subtask 1: 21 / 21
• Subtask 2: 22 / 22
• Subtask 3: 13 / 13
• Subtask 4: 28 / 28
• Subtask 5: 16 / 16