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IWhisper#467
2024/9/22镜像同步9 回复
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第二题longlong加哈希记录频率能过<br>【 在 IWhisper#289 的大作中提到: 】<br><font class="f006">: 第二题怎么也改不出来 </font>
/**<br><span class="emoji" style="font-size: 16px"> </span>* <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span>author: <span class="emoji" style="font-size: 16px"> </span>haoyunbaobei<br><span class="emoji" style="font-size: 16px"> </span>* <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span>created: 22.09.2024 10:08:59<br><span class="emoji" style="font-size: 16px"> </span>**/<br>#include <bits/stdc++.h><br><br>using namespace std;<br><br>int main() {<br><span class="emoji" style="font-size: 16px"> </span> ios::sync_with_stdio(false);<br><span class="emoji" style="font-size: 16px"> </span> cin.tie(nullptr);<br><span class="emoji" style="font-size: 16px"> </span> int t;<br><span class="emoji" style="font-size: 16px"> </span> cin >> t;<br><span class="emoji" style="font-size: 16px"> </span> while (t--) {<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> int n;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> cin >> n;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> vector<int> vi(n);<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> long long sum = 0;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> for (int i = 0; i < n; i++) {<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> cin >> vi[i];<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> sum = sum + vi[i];<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> }<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> long long pro = sum * (n - 2);<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> if (pro % n) {<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> cout << 0 << '\n';<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> continue;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> }<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> long long target = sum - pro / n;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> // cout << "sum: " << sum << '\n';<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> // cout << "pro: " << pro << '\n';<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> // cout << "target: " << target << '\n';<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> unordered_map<int, int> mp;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> int ans = 0;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> for (int i = 0; i < n; i++) {<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> if (i == 0) {<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> mp[vi[i]]++;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> continue;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> }<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> if (mp.find(target - vi[i]) != mp.end()) {<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> ans += mp[target - vi[i]];<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> }<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> mp[vi[i]]++;<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> }<br><span class="emoji" style="font-size: 16px"> </span> <span class="emoji" style="font-size: 16px"> </span> cout << ans << '\n';<br><span class="emoji" style="font-size: 16px"> </span> }<br><span class="emoji" style="font-size: 16px"> </span> return 0;<br>}
用了哈希了没用long<img src="/img/ubb/ema/1.gif" alt="ema1" style="display:inline;border-style:none"><br>【 在 IWhisper#147 的大作中提到: 】<br><font class="f006">: 第二题longlong加哈希记录频率能过 </font>
第三题我吐了<img src="/img/ubb/ema/2.gif" alt="ema2" style="display:inline;border-style:none"><br>【 在 IWhisper#289 的大作中提到: 】<br><font class="f006">: 用了哈希了没用long<img src="/img/ubb/ema/1.gif" alt="ema1" style="display:inline;border-style:none"> </font>