Submission #630821

#	Time	Username	Problem	Language	Result	Execution time	Memory
630821		tmncollins	Mutating DNA (IOI21_dna)	C++17	100 / 100	39 ms	10892 KiB

dna

#include "dna.h"
#include <stdio.h>
#include <vector>
#include <string>
#include <map>
#include <iostream>
#include <cmath>
#include <algorithm>

// g++ grader.cpp dna.cpp -o dna

using namespace std;

map<char, int> base;

struct pref {
    int arr[3][3], copy[3][3];

    pref() {
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                arr[i][j] = copy[i][j] = 0;
            }
        }
    }

    void add(pref p) {
        for (int a = 0; a < 3; a++) {
            for (int b = 0; b < 3; b++) {
                arr[a][b] += p.arr[a][b];
            }
        }
    }

    void subt(pref p) {
        for (int a = 0; a < 3; a++) {
            for (int b = 0; b < 3; b++) {
                arr[a][b] -= p.arr[a][b];
            }
        }
    }

    int dist() {
        int d = 0;

        for (int i = 0; i < 3; i++) {
            int a = 0, b = 0;
            for (int j = 0; j < 3; j++) {
                copy[i][j] = arr[i][j];
                a += arr[i][j];
                b += arr[j][i];
            }
            if (a != b) return -1;
        }

        int unpaired = 0;

        // directly swap a and b
        for (int a = 0; a < 3; a++) {
            for (int b = 0; b < a; b++) {
                int v = min(arr[a][b], arr[b][a]);
                copy[a][b] -= v;
                copy[b][a] -= v;
                d += v;
                unpaired += copy[a][b] + copy[b][a];
            }
        }

        unpaired /= 3;
        unpaired *= 2;

        return d + unpaired;

    }

    void output() {
        cout << "==========\n";
        for (int k = 0; k < 3; k++) {
            for (int i = 0; i < 3; i++)
                cout << arr[k][i] << " ";
            cout << "\n";
        }
        cout << "==========\n";
    }
};

vector<pref> prefix;

void init(string a, string b) {
    int size = a.size() + 1;
    prefix = vector<pref> (size);
    base['A'] = 0;
    base['C'] = 1;
    base['T'] = 2;

    prefix[0] = pref(); // A, C, T (1), A, C, T (2), diff

    for (int k = 1; k < size; k++) {
        int i = k-1;
        prefix[k] = prefix[k-1];
        int base_a = base[a[i]];
        int base_b = base[b[i]];

        prefix[k].arr[base_a][base_b]++;
//        prefix[k].arr[base_b][base_a]++;
    }

}

int get_distance(int x, int y) {
    pref a = prefix[x], b = prefix[y+1];
    b.subt(a);
//    b.output();

    return b.dist();
}

/*
*/

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