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64 lines
1.4 KiB
64 lines
1.4 KiB
#include <bits/stdc++.h>
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using namespace std;
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typedef long long LL;
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/*
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4
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1 2 3 4
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*/
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const int N = 110;
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struct Node {
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int num; // 啥数
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int left, right; // 左侧是哪个节点，右侧是哪个节点
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} a[N];
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int st[N];
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int n;
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LL res;
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string finalPath;
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void dfs(int r, LL sum, string path) { // u:本轮选择哪个靶子， r:剩余几次机会 sum:已经取得的累加和
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if (r == 0) {
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if (sum > res) {
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res = sum;
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finalPath = path;
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}
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return;
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}
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for (int u = 1; u <= n; u++) {
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if (!st[u]) {
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int L = a[u].left, R = a[u].right;
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st[u] = 1; // u号靶子被标识为已放倒
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a[L].right = R;
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a[R].left = L;
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// 深搜
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dfs(r - 1, sum + a[L].num * a[u].num * a[R].num, path + to_string(u));
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// 回溯
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a[L].right = u;
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a[R].left = u;
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st[u] = 0; // u被扶了起来
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}
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}
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}
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int main() {
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cin >> n;
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for (int i = 1; i <= n; i++) cin >> a[i].num;
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// 左右哨兵
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a[0].num = 1;
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a[n + 1].num = 1;
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// 预处理
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for (int i = 1; i <= n; i++) {
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a[i].left = i - 1;
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a[i].right = i + 1;
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}
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dfs(n, 0, "");
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cout << res << endl;
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cout << finalPath << endl;
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return 0;
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} |