Submission #437745

#	Time	Username	Problem	Language	Result	Execution time	Memory
437745		jh05013	Mutating DNA (IOI21_dna)	C++17	100 / 100	51 ms	5440 KiB

dna

#include <bits/stdc++.h>
using namespace std;
const int MXN = 100100;
int zac[MXN], zat[MXN], zca[MXN], zct[MXN], zta[MXN], ztc[MXN];

void init(string a, string b){
    int n = a.size();
    for(int i=1; i<=n; i++){
        zac[i]+= zac[i-1], zat[i]+= zat[i-1];
        zca[i]+= zca[i-1], zct[i]+= zct[i-1];
        zta[i]+= zta[i-1], ztc[i]+= ztc[i-1];
        char A = a[i-1], B = b[i-1];
        if(A == 'A'){
            if(B == 'C') zac[i]++;
            if(B == 'T') zat[i]++;
        }
        if(A == 'C'){
            if(B == 'A') zca[i]++;
            if(B == 'T') zct[i]++;
        }
        if(A == 'T'){
            if(B == 'A') zta[i]++;
            if(B == 'C') ztc[i]++;
        }
    }
}

int get_distance(int x, int y){
    int qac = zac[y+1]-zac[x], qat = zat[y+1]-zat[x];
    int qca = zca[y+1]-zca[x], qct = zct[y+1]-zct[x];
    int qta = zta[y+1]-zta[x], qtc = ztc[y+1]-ztc[x];
    if(qac+qat != qca+qta) return -1;
    if(qca+qct != qac+qtc) return -1;
    if(qta+qtc != qat+qct) return -1;

    // correcting two letters per swap
    int acca = min(qac, qca);
    qac-= acca, qca-= acca;
    int atta = min(qat, qta);
    qat-= atta, qta-= atta;
    int cttc = min(qct, qtc);
    qct-= cttc, qtc-= cttc;
	return acca + atta + cttc + 2*max(qac, qca);
}

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