bpstudy で出会い系ペアプロがまさかの LRU だったという話

#include <string.h>
#include <stdio.h>

#define SIZE 2

static char key[SIZE][1024];
static char value[SIZE][1024];
static int now = 0;

void put(const char* k, const char* v)
{
  int i;
  int found = 0;
  // 重複チェック
  for (i = 0; i < now; i++) {
    if (strcmp(key[i], k) == 0) {
      found = 1;
      break;
    }
  }
  if (found) {
    // 重複があったのでつめる
    for (i++; i < now; i++) {
      strcpy(key[i - 1], key[i]);
	strcpy(value[i - 1], value[i]);
    }
    now--;
  } else {
    // サイズがいっぱいだったら、一番古いのをすてて、他のを１つ詰める
    if (now == SIZE) {
      for (i = 1; i < SIZE; i++) {
	strcpy(key[i - 1], key[i]);
	strcpy(value[i - 1], value[i]);
      }
      now--;
    }
  }
  // 最新のスロットに値を入れる
  strcpy(key[now], k);
  strcpy(value[now], v);
  now++;
}

const char* get(const char* k)
{
  int i, j;
  char v[1024];
  for(i = 0; i < now && strcmp(key[i], k) != 0; i++)
    ;
  if(i == now)
    return NULL;
  strcpy(v, value[i]);
  for (j = i+1; j < now; j++) {
    strcpy(key[j - 1], key[j]);
    strcpy(value[j - 1], value[j]);
  }
  strcpy(key[now - 1], k);
  strcpy(value[now - 1], v);
  return value[now - 1];
}

static int status = 0;
static void _ok(int line, int t)
{
  if (! t) {
    status = 1;
  }
  printf("%s at line %d\n", t ? "ok" : "not ok", line);
}

static void _is(int line, const char* x, const char* y)
{
  int t = strcmp(x, y) == 0;
  if (! t) {
    status = 1;
    printf("not ok %s != %s at line %d\n", x, y, line);
  } else {
    printf("ok at line %d\n", line);
  }
}

#define ok(x)  _ok(__LINE__, x)
#define is(s, t)  _is(__LINE__, s, t)

int main(int argc, char **argv)
{
  put("a", "danA");
  ok(strcmp(key[0], "a") == 0);
  ok(strcmp(value[0], "danA") == 0);
  ok(now == 1);
  
  put("b", "danB");
  ok(strcmp(key[0], "a") == 0);
  ok(strcmp(value[0], "danA") == 0);
  ok(strcmp(key[1], "b") == 0);
  ok(strcmp(value[1], "danB") == 0);
  ok(now == 2);
  
  put("c", "danC");
  ok(strcmp(key[0], "b") == 0);
  ok(strcmp(value[0], "danB") == 0);
  ok(strcmp(key[1], "c") == 0);
  ok(strcmp(value[1], "danC") == 0);
  ok(now == 2);
  
  ok(get("a") == NULL);
  ok(strcmp(key[0], "b") == 0);
  ok(strcmp(value[0], "danB") == 0);
  ok(strcmp(key[1], "c") == 0);
  ok(strcmp(value[1], "danC") == 0);
  ok(now == 2);
  
  is(get("b"), "danB");
  is(key[0], "c");
  is(value[0], "danC");
  is(key[1], "b");
  is(value[1], "danB");
  ok(now == 2);
  
  put("c", "zzzC");
  is(key[0], "b");
  is(value[0], "danB");
  is(key[1], "c");
  is(value[1], "zzzC");
  
  return status;
}