Submission #1187048

#	Time	Username	Problem	Language	Result	Execution time	Memory
1187048		North1304	Coins (IOI17_coins)	C++20	100 / 100	9 ms	584 KiB

coins

#include "coins.h"
using namespace std;

// Arnavaz's move: flip one coin so that the new XOR‐parity equals c
vector<int> coin_flips(vector<int> b, int c) {
    int P = 0;
    for (int i = 0; i < 64; i++) {
        if (b[i]) P ^= i;
    }
    // flip position
    return {P ^ c};
}

// Shahrnaz's move: compute XOR of all tail‐positions to find c
int find_coin(vector<int> b) {
    int P = 0;
    for (int i = 0; i < 64; i++) {
        if (b[i]) P ^= i;
    }
    return P;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 10 / 10
• Subtask 4: 15 / 15
• Subtask 5: 50 / 50