89 lines
2.7 KiB
C
89 lines
2.7 KiB
C
#include <stdio.h>
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#include <string.h>
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#define MAX 100
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int getLCS(char* text1, char* text2) {
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int t1_len = strlen(text1);
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int t2_len = strlen(text2);
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int dp[MAX][MAX] = {0};
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for (int i = 1; i <= t1_len; i++) {
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for (int j = 1; j <= t2_len; j++) {
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if (text1[i - 1] == text2[j - 1]) {
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//找到一个 lcs 的元素，继续往前找
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dp[i][j] = 1 + dp[i - 1][j - 1];
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} else {//谁能让 lcs 最长，就取谁的值
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dp[i][j] = (dp[i - 1][j] > dp[i][j - 1])?
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dp[i - 1][j] : dp[i][j - 1];
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}
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}
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}
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return dp[t1_len][t2_len];
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}
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void getLCSTable(int dp[MAX][MAX], char* text1, char* text2, char b[MAX][MAX]) {
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int t1_len = strlen(text1);
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int t2_len = strlen(text2);
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for (int i = 1; i <= t1_len; i++) {
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for (int j = 1; j <= t2_len; j++) {
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if (text1[i - 1] == text2[j - 1]) {
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dp[i][j] = 1 + dp[i - 1][j - 1];
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b[i][j] = 'X'; // LCS元素，使用 'X' 作为占位符
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} else if (dp[i - 1][j] >= dp[i][j - 1]) {
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dp[i][j] = dp[i - 1][j];
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b[i][j] = '|'; // 取上面的值
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} else {
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dp[i][j] = dp[i][j - 1];
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b[i][j] = '-'; // 取左边的值
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}
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}
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}
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}
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void printLCSTable(char b[MAX][MAX], char* t1, char* t2, int l1, int l2) {
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printf("\t");
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for (int j = 0; j < l2; j++)
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printf("%c\t", t2[j]);
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printf("\n");
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for (int i = 0; i <= l1; i++) {
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printf("%c\t", (i == 0) ? ' ' : t1[i - 1]);
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for (int j = 0; j <= l2; j++) {
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if (i == 0 && j == 0) {
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printf("\t");
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} else {
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printf("%c\t", b[i][j]);
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}
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}
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printf("\n");
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}
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}
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void printLCSString(char b[MAX][MAX], char* x, int i, int j) {
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if (i == 0 || j == 0) return;
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if (b[i][j] == 'X') {
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printLCSString(b, x, i - 1, j - 1);
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// 打印当前字符
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printf("%c", x[i - 1]);
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} else if (b[i][j] == '|') {
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printLCSString(b, x, i - 1, j);
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} else {
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printLCSString(b, x, i, j - 1);
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}
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}
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int main() {
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char t1[] = "ABCB";
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char t2[] = "BDCA";
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printf("字符串: %s 和字符串: %s 的 LCS 长度为: %d\n", t1, t2, getLCS(t1, t2));
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printf("--------------------------------\n");
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int dp[MAX][MAX] = {0};
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char b[MAX][MAX] = {0};
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getLCSTable(dp, t1, t2, b);
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printLCSTable(b, t1, t2, strlen(t1), strlen(t2));
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printf("-------------------------------\n");
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printf("LCS 字符串为: ");
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printLCSString(b, t1, strlen(t1), strlen(t2));
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printf("\n");
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return 0;
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}
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