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simplified-edit-distance.c
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simplified-edit-distance.c
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#include "simplified-edit-distance.h"
#include "stdio.h"
#include "stdlib.h"
int MinEditOpsAux(int **dp, int **op, char *x, char *y, int i, int j, int m,
int n) {
if (i == m)
return n - j;
if (j == n)
return m - i;
if (dp[i][j] != -1)
return dp[i][j];
if (x[i] == y[j]) {
dp[i][j] = MinEditOpsAux(dp, op, x, y, i + 1, j + 1, m, n);
op[i][j] = nothing;
return dp[i][j];
}
// replace x[i] with y[j]
int ops_if_replace = 1 + MinEditOpsAux(dp, op, x, y, i + 1, j + 1, m, n);
// insert y[j] before x[i]
int ops_if_insert = 1 + MinEditOpsAux(dp, op, x, y, i, j + 1, m, n);
// delete x[i]
int ops_if_delete = 1 + MinEditOpsAux(dp, op, x, y, i + 1, j, m, n);
dp[i][j] = ops_if_replace;
op[i][j] = replace;
if (ops_if_insert < dp[i][j]) {
dp[i][j] = ops_if_insert;
op[i][j] = insert;
}
if (ops_if_delete < dp[i][j]) {
dp[i][j] = ops_if_delete;
op[i][j] = delete;
}
return dp[i][j];
}
edit_distance_result MinEditOps(char *x, char *y, int m, int n) {
edit_distance_result result;
int i, j;
int **dp = (int **)malloc(sizeof(int *) * (m + 1));
int **op = (int **)malloc(sizeof(int *) * (m + 1));
for (i = 0; i <= m; i++)
dp[i] = (int *)malloc(sizeof(int) * (n + 1)),
op[i] = (int *)malloc(sizeof(int) * (n + 1));
for (i = 0; i <= m; i++)
for (j = 0; j <= n; j++)
dp[i][j] = -1;
result.ops_required = MinEditOpsAux(dp, op, x, y, 0, 0, m, n);
result.dp = dp;
result.op = op;
return result;
}
void PrintEditSequence(int **op, char *x, char *y, int i, int j, int m, int n) {
if (i == m) {
if (j < n)
printf("copy word2[%d...%d]", j, n);
return;
}
if (j == n) {
if (i < m)
printf("delete word1[%d...%d]", i, m);
return;
}
switch (op[i][j]) {
case replace:
printf("replace %c with %c\n", x[i], y[j]);
PrintEditSequence(op, x, y, i + 1, j + 1, m, n);
break;
case insert:
printf("insert %c\n", y[j]);
PrintEditSequence(op, x, y, i, j + 1, m, n);
break;
case delete:
printf("delete %c\n", x[i]);
PrintEditSequence(op, x, y, i + 1, j, m, n);
break;
default:
PrintEditSequence(op, x, y, i + 1, j + 1, m, n);
break;
}
}