例题9-8(uva-1625)

#include <iostream>
#include <istream>
#include <sstream>
#include <vector>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <numeric>
#include <chrono>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <cstdio>
#include <iomanip>


#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <iterator>
using namespace std;
const int maxn = 5007,INF = 0x3f3f3f3f,maxm = 26;
int cnt[maxn][maxn],dp[maxn][maxn],afirst[maxm],alast[maxm],bfirst[maxm],blast[maxm];
char str[maxn], str2[maxn];

int main()
{
    
    
	int t;
	cin >> t;
	while (t--) {
    
    
		cin >> (str + 1) >> (str2 + 1);
		int alen = strlen(str + 1), blen = strlen(str2 + 1),c;
		for (int i = 0; i < maxm; i++) {
    
    
			afirst[i] = bfirst[i] = INF;
			alast[i] = blast[i] = 0;
		}
		for (int i = 1; i <= alen; i++) {
    
    
			alast[str[i] - 'A'] = i;
			afirst[str[i] - 'A'] = min(i, afirst[str[i] - 'A']);
		}
		for (int i = 1;i<=blen;i++)
		{
    
    
			blast[str2[i] - 'A'] = i;
			bfirst[str2[i] - 'A'] = min(i, bfirst[str2[i] - 'A']);
		}
		cnt[0][0] = 0;

		for (int i = 0; i <= alen; i++) {
    
    
			for (int j = 0; j <= blen; j++) {
    
    
				if (!i && !j)continue;
				if (i) {
    
    
					cnt[i][j] = cnt[i - 1][j];
					c = str[i] - 'A';
					if (afirst[c] == i && bfirst[c] > j) cnt[i][j]++;
					if (alast[c] == i && blast[c] <= j) cnt[i][j]--;
				}
				if (j) {
    
    
					cnt[i][j] = cnt[i][j - 1];
					c = str2[j] - 'A';
					if (bfirst[c] == j && afirst[c] > i) cnt[i][j]++;
					if (blast[c] == j && alast[c] <= i) cnt[i][j]--;
				}
			}
		}
		for (int i = 0; i <= alen; i++)
			for (int j = 0; j <= blen; j++) {
    
    
				if (!i && !j) continue;
				dp[i][j] = INF;
				if (i) dp[i][j] = min(dp[i][j], dp[i - 1][j] + cnt[i - 1][j]);
				if (j) dp[i][j] = min(dp[i][j], dp[i][j - 1] + cnt[i][j - 1]);
			}
		cout << dp[alen][blen] << endl;
	}
	return 0;
}