Codeforces Round 578 (Div. 2) E 题 Compress Words（扩展 KMP）-代码

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e5 + 5;
int n;
string s[N];
// z[i]表示 s 和 s[i:] 匹配的最大前缀长度
vector<int> zfunc(const string& s) {
	int n = s.size();
	vector<int> z(n);
	for (int i = 1, l = 0, r = 0; i < n; i++) {
		if (i <= r) z[i] = min(z[i - l], r - i + 1);
		while (i + z[i] < n && s[i + z[i]] == s[z[i]]) z[i]++;
		if (i + z[i] - 1 > r) l = i, r = i + z[i] - 1;
	}
	z[0] = n;
	return z;
}
void solve()
{
	cin >> n;
	for (int i = 1; i <= n; i++)
	{
		cin >> s[i];
	}
	string ans = s[1];
	for (int i = 2; i <= n; i++)
	{
		string str = s[i];
		for (int j = max((int)((int)(ans.size()) - (int)(s[i].size())), 0ll); j < ans.size(); j++)
		{
			str.push_back(ans[j]);
		}
		vector<int>z = zfunc(str);
		int res = 0;
		for (int j = s[i].size(); j < str.size(); j++)
		{
			if (z[j] + j == str.size())
			{
				res = z[j];
				break;
			}
		}
		for (int j = res; j < s[i].size(); j++)
		{
			ans.push_back(s[i][j]);
		}
	}
	cout << ans << endl;
}
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	int test = 1;
	// cin >> test;
	for (int i = 1; i <= test; i++)
	{
		solve();
	}
	return 0;
}