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https://git.sb/baoshuo/OI-codes.git
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57 lines
1.1 KiB
C++
57 lines
1.1 KiB
C++
#include <iostream>
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#include <algorithm>
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#include <utility>
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#include <vector>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 1e5 + 5;
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int n, siz[N];
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long long dis;
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std::pair<long long, int> d[N];
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std::vector<std::pair<int, int>> ans;
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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cin >> n;
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for (int i = 1; i <= n; i++) {
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cin >> d[i].first;
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d[i].second = i;
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}
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std::fill(siz + 1, siz + 1 + n, 1);
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std::sort(d + 1, d + 1 + n);
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for (int i = n; i > 1; i--) {
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long long t = d[i].first - n + (siz[i] << 1);
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int p = std::lower_bound(d + 1, d + 1 + n, std::make_pair(t, 0)) - d;
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if (d[p].first != t) {
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cout << -1 << endl;
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exit(0);
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}
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ans.emplace_back(d[i].second, d[p].second);
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siz[p] += siz[i];
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dis += siz[i];
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}
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if (dis != d[1].first) {
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cout << -1 << endl;
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} else {
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for (auto e : ans) {
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cout << e.first << ' ' << e.second << endl;
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}
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}
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return 0;
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}
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