动画演示编辑距离

const char* s = "ecllipse"; int m = strlen(s);
const char *t = "ellipsis"; int n = strlen(t);
int d[64][64];
int pt = 50;

void my_pause(int n = pt) {
  int paused = 0;
  for (int i = 0; (i < n) || paused; i++) {
    usleep(10000);
    int ch = getch();
    if (ch == ERR) continue;
    else if (ch == 'q' || ch == 'Q') exit(0);
    else if (ch == ' ') paused = !paused;
    else break;
  }
}

void display(int ii, int jj, int flag) {
  for (int i = 0; i <= m; i++) {
    if (i == ii) attron(COLOR_PAIR(flag));
    mvaddch(3, 16+i*2, s[i] ? : ' '); // gcc feature
    if (i == ii) attroff(COLOR_PAIR(flag));
  }

  for (int j = 0; j <= n; j++) {
    if (j == jj) attron(COLOR_PAIR(flag));
    mvaddch(5, 16+j*2, t[j] ? : ' ');
    if (j == jj) attroff(COLOR_PAIR(flag));
  }

  for (int i = 0; i <= m; i++)
    for (int j = 0; j <= n; j++) {
      int  v = d[i][j];
      char s[16] = "?";
      if (v >= 0) sprintf(s, "%d", v, d[i][j]);
      if (i == ii && j == jj) attron(COLOR_PAIR(flag));
      mvprintw(7+i*2, 10+j*6, "%s", s);
      if (i == ii && j == jj) attroff(COLOR_PAIR(flag));
    }
  refresh(); my_pause();
}

inline int min3 (int a, int b, int c) {
  int min = a;
  if (b < min) min = b;
  if (c < min) min = c;
  return min + 1;
}

int edit_distance() {
  // 把s的前i个字符转换为""需要i次删除
  for (int i = 0; i <= m; i++) d[i][0] = i;

  // 把""转换为t的前j个字符需要j次插入
  for (int j = 0; j <= n; j++) d[0][j] = j;

  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (s[i - 1] == '-' || s[i - 1] == t[j - 1]) {
        d[i][j] = d[i - 1][j - 1]; // 相同字符无需操作
        display(i-1, j-1, 1);
      }
      else {
        int a = d[i - 1][j]; // 删除
        display(i-1, j, 2);
        int b = d[i][j - 1]; // 插入
        display(i, j-1, 3);
        int c = d[i - 1][j - 1]; // 替换
        display(i-1, j-1, 4);
        d[i][j] = min3(a, b, c);
      }
      display(i, j, 5);
    }
  }

  return d[m][n];
}

int main (int argc, char* argv[]) {
  if (argc == 2) pt = atoi(argv[1]);

  memset(d, -1, sizeof(d));

  initscr(); start_color();
  init_pair(1, COLOR_RED, COLOR_BLACK);
  init_pair(2, COLOR_GREEN, COLOR_BLACK);
  init_pair(3, COLOR_CYAN, COLOR_BLACK);
  init_pair(4, COLOR_MAGENTA, COLOR_BLACK);
  init_pair(5, COLOR_WHITE, COLOR_GREEN);
  cbreak(); noecho(); timeout(0); curs_set(0);
  atexit((void (*)())endwin);

  int n = edit_distance();
  display(m, n, 0);
  my_pause(1000);
  return n;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ncurses.h>