Submission #1556153

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Source Code Expand

#include <algorithm>
#include <cstdio>
#include <map>
#include <numeric>
#include <vector>
#define repeat(i, n) for (int i = 0; (i) < int(n); ++(i))
#define whole(x) begin(x), end(x)
using namespace std;

int solve(int n, vector<int> const & a, vector<int> const & b) {
    int sum_a = accumulate(whole(a), 0, bit_xor<int>());
    map<int, map<int, int> > g;
    auto link = [&](int x, int y) {
        if (x != y) {
            g[x][y] += 1;
        }
    };
    auto unlink = [&](int x, int y) {
        g[x][y] -= 1;
        if (not g[x][y]) {
            g[x].erase(y);
            if (g[x].empty()) {
                g.erase(x);
            }
        }
    };
    repeat (i, n) {
        link(b[i], a[i]);
    }
    int result = 0;
    for (int i = sum_a; not g.empty(); ++ result) {
        if (not g.count(i)) {
            int j = g.begin()->first;
            int k = g.begin()->second.begin()->first;
            if (not g.count(k)) return -1;
            unlink(j, k);
            link(j, i);
            i = k;
        } else {
            int j = g[i].begin()->first;
            unlink(i, j);
            i = j;
        }
    }
    return result;
}

int main() {
    int n; scanf("%d", &n);
    vector<int> a(n); repeat (i, n) scanf("%d", &a[i]);
    vector<int> b(n); repeat (i, n) scanf("%d", &b[i]);
    int result = solve(n, a, b);
    printf("%d\n", result);
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:49:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     int n; scanf("%d", &n);
                           ^
./Main.cpp:50:55: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     vector<int> a(n); repeat (i, n) scanf("%d", &a[i]);
                                                       ^
./Main.cpp:51:55: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     vector<int> b(n); repeat (i, n) scanf("%d", &b[i]);
                                                       ^

Judge Result