Files
suanfa/public/c/ch3/lcs/lcs2.c
T
2026-06-15 09:00:38 +08:00

96 lines
2.3 KiB
C

#include <stdio.h>
#include <string.h>
// 打印LCS的函数
void PrintLCS(int path[][100], char *x, int i, int j) {
if (i == 0 || j == 0) {
return;
}
if (path[i][j] == 0) {
PrintLCS(path, x, i - 1, j - 1);
printf("%c", x[i - 1]);
} else if (path[i][j] == 1) {
PrintLCS(path, x, i - 1, j);
} else {
PrintLCS(path, x, i, j - 1);
}
}
// 找到LCS的长度
int findLCS(int dp[][100], char *A, int n, char *B, int m) {
// 初始化dp数组
for (int i = 0; i <= n; i++) {
for (int j = 0; j <= m; j++) {
dp[i][j] = 0; // 数组初始化
}
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) { // 执行状态转移方程
if (A[i - 1] == B[j - 1]) {
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];
}
}
}
return dp[n][m];
}
int main() {
char x[] = "w8xta2px0i1jf4jfn8du8dk1fk2kvchd32";
char y[] = "i3xsmdxwuv6a2yt520";
int m = strlen(x);
int n = strlen(y);
// 创建二维数组
int c[101][101]; // 101用于存储m+1和n+1的值
int path[101][101]; // 路径数组
// 初始化二维数组
for (int i = 0; i <= m; i++) {
c[i][0] = 0;
}
for (int i = 0; i <= n; i++) {
c[0][i] = 0;
}
// 实现LCS逻辑
for (int i = 1; i <= m; i++) {
for (int j = 1; j <= n; j++) {
if (x[i - 1] == y[j - 1]) {
c[i][j] = c[i - 1][j - 1] + 1;
} else if (c[i - 1][j] >= c[i][j - 1]) {
c[i][j] = c[i - 1][j];
path[i][j] = 1; // 来自上方
} else {
c[i][j] = c[i][j - 1];
path[i][j] = -1; // 来自左侧
}
}
}
// 输出c数组
printf("c:\n");
for (int i = 0; i <= m; i++) {
for (int j = 0; j <= n; j++) {
printf("%d\t", c[i][j]);
}
printf("\n");
}
// 输出path数组
printf("path:\n");
for (int i = 0; i <= m; i++) {
for (int j = 0; j <= n; j++) {
printf("%d\t", path[i][j]);
}
printf("\n");
}
printf("%s与%s的最长公共子序列为:\n", x, y);
PrintLCS(path, x, m, n);
return 0;
}