int cmp(const void *a, const void *b) {
    return *(int *)a - *(int *)b;
}

int* avoidFlood(int* rains, int rainsSize, int* returnSize) {
    int *result = (int *)malloc(sizeof(int) * rainsSize);
    int *nextRain = (int *)malloc(sizeof(int) * rainsSize);
    int *fullLakes = (int *)malloc(sizeof(int) * rainsSize);
    int fullLakesSize = 0, nextRainSize = 0;
    memset(result, 0, sizeof(int) * rainsSize);
    memset(nextRain, 0, sizeof(int) * rainsSize);
    memset(fullLakes, 0, sizeof(int) * rainsSize);

    for (int i = 0; i < rainsSize; i++) {
        if (rains[i] > 0) {
            for (int j = 0; j < fullLakesSize; j++) {
                if (fullLakes[j] == rains[i]) {
                    *returnSize = 0;
                    return NULL;
                }
            }
            fullLakes[fullLakesSize++] = rains[i];
            nextRain[nextRainSize++] = i;
            result[i] = -1;
        } else {
            if (nextRainSize == 0) {
                result[i] = 1;
            } else {
                qsort(nextRain, nextRainSize, sizeof(int), cmp);
                int lakeToDry = -1;
                for (int j = 0; j < nextRainSize; j++) {
                    if (rains[nextRain[j]] > 0) {
                        lakeToDry = rains[nextRain[j]];
                        break;
                    }
                }
                if (lakeToDry == -1) {
                    result[i] = 1;
                } else {
                    result[i] = lakeToDry;
                    for (int j = 0; j < fullLakesSize; j++) {
                        if (fullLakes[j] == lakeToDry) {
                            fullLakes[j] = fullLakes[--fullLakesSize];
                            break;
                        }
                    }
                    for (int j = 0; j < nextRainSize; j++) {
                        if (rains[nextRain[j]] == lakeToDry) {
                            nextRain[j] = nextRain[--nextRainSize];
                            break;
                        }
                    }
                }
            }
        }
    }

    *returnSize = rainsSize;
    return result;
}