动态规划复习-HDU1159

最长公共子序列问题，经典dp

#include 
#include 
#include 
using namespace std;

char a[2000], b[2000];
int al, bl, m;
int dp[2000][2000];
int main() {

	while (cin >> a >> b) {
		al = strlen(a);
		bl = strlen(b);
		bool one = false;
		for (int i = 0; i < al; ++i) {
			if (a[i] == b[0]) {
				dp[i][0] = 1;
				one = true;
			} else {
				dp[i][0] = one ? 1 : 0;
			}
		}
		one = false;
		for (int i = 0; i < bl; ++i) {
			if (a[0] == b[i]) {
				dp[0][i] = 1;
				one = true;
			} else {
				dp[0][i] = one ? 1 : 0;
			}
		}
		m = 0;
		for (int i = 1; i < al; ++i) {
			for (int j = 1; j < bl; ++j) {
				if (a[i] == b[j])
					dp[i][j] = dp[i - 1][j - 1] + 1;
				else
					dp[i][j] = dp[i - 1][j] > dp[i][j - 1] ? dp[i - 1][j] : dp[i][j - 1];
				if (dp[i][j] > m)
					m = dp[i][j];
			}
		}
		cout << m << endl;
	}
	return 0;
}