int bi_search(int numbers[], int b_n, int e_n, int val) {
    if (b_n > e_n)
        return 0;
    int mid = (b_n + e_n) / 2;
    if (numbers[mid] == val) {
        return 1;
    }
    // 这里二分查找明显不是最优,因为numbers已经排好序,所以下面只需要查找一侧即可
    if (bi_search(numbers, b_n, mid-1, val) || bi_search(numbers, mid+1, e_n, val)) {
        return 1;
    }
    return 0;
}
Exemple #2
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 int bi_search(vector<int>& v, int i, int j, int target) {
     int mid = (i+j)/2;
     if (i>j && i>=v.size()) // right out
         return 2;
     else if (i>j && j<0) // left  out
         return -1;
     else if (i > j)     // not found
         return 0;
     if (v[mid] == target)
         return 1;
     else if (v[mid] < target)
         return bi_search(v, mid+1, j, target);
     else if (v[mid] > target)
         return bi_search(v, i, mid-1, target);
     // return 1 found, -1 less, 2 biger, 0 not found
 }
Exemple #3
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int main()
{
	SeqList sl;
	int i, j, k, t;
	printf("input the elements in escendant order:\n");
	i = 0;
	scanf("%d", &(sl.data[i]));
	while(i < N-1){
		scanf("%d", &t);
		if(t > sl.data[i]){
			i++;
			sl.data[i] = t;
		}else{
			printf("error, must bigger than %d\n", sl.data[i]);
		}
	}
	sl.length = N;
	printf("input the key:\n");
	scanf("%d", &k);
	j = bi_search(&sl, k);
	printf("-------------------\n");
	if(j >= 0){
		printf("found : data[%d]\n", j);
	}else{
		printf("%d is not been found\n", k);
	}

	return 0;
}
Exemple #4
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int bi_delete(int key, int a[], int *np)
    {
    int p;
    int i;
    if (*np > 0)
        {
        if ((p = bi_search(key, a, *np)) < 0) return -1;
        for (i = p+1; i < *np; i++) a[i-1] = a[i];
        (*np)--;
        return p;
        }
    return -1;
    }
Exemple #5
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void li_test(int a[], int n)
    {
    int i;
    long t1, t2;
    t1 = get_tick();
    for (i = 0; i < LOOP; i++) bi_search(random(30000), a, n);
    t2 = get_tick();
    printf("\n li_search %d loops ellapse %ld ticks.", LOOP, diff_tick(t1,t2));
    t1 = get_tick();
    for (i = 0; i < LOOP; i++) bii_search(random(30000), a, n);
    t2 = get_tick();
    printf("\n lfi_search %d loops ellapse %ld ticks.", LOOP, diff_tick(t1,t2));
    }
Exemple #6
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    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        if (matrix.empty()) return false;
        int n = matrix[0].size();
        int i = 0;
        int j = matrix.size() -1;

        while (i <= j) {
            int mid = (i+j)/2;
            int flag = bi_search(matrix[mid], 0, n, target);
            if (flag == 1) return true;
            if (flag == 0) return false;
            if (flag == -1) j = mid-1;
            if (flag == 2) i = mid+1;
        }
        return false;
    }
Exemple #7
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void interpret(int a[], int *np, int N)
    {
    char command[2];
    char key[2];
    int p;
    while (command[0] != 'q')
        {
        printf("\nInput command ->");
        scanf("%1s", command);
        scanf("%1s", &key);
        switch (command[0])
            {
            case 'i' :
            case 'I' : if (*np < N)
                           {
                           bi_insert(key[0], a, np);
                           printf("\n   Successful insert.");
                           }
                       else
                           printf("\n   Error : Table full.");
                       break;
            case 'd' :
            case 'D' : if (bi_delete(key[0], a, np) < 0)
                           printf("\n   Error : Table Empty.");
                       else
                           printf("\n   Successful delete.");
                       break;
            case 's' :
            case 'S' : if ((p = bi_search(key[0], a, *np)) < 0)
                           printf("\n   Error : Can'f find that key");
                       else
                           printf("\n   Ok! find in %d th position", p);
                       break;
            case 'f' :
            case 'F' : if ((p = bii_search(key[0], a, *np)) < 0)
                           printf("\n   Error : Can't find that key");
                       else
                           printf("\n   Ok ! find in %d th position & move front", p);
                       break;
            case 'l' :
            case 'L' : bi_list(a, *np);
                       break;
            }
        printf("  n = %d", *np);
        }
    }
int *twoSum(int numbers[], int n, int target) {
    int i = 0, j = n -1, k, sub_val;
    int ans[2];
    int *tmp = (int *)malloc(n * sizeof(int));
    memcpy(tmp, numbers, n * sizeof(int));
    qsort((void *)numbers, n, sizeof(int), compare);
    if(false) {
        //通过二分查找确定
        for (i = 0; i < n; ++i) {
            sub_val = target - numbers[i];
            if (bi_search(numbers, i+1, n-1, sub_val)) {
                break;
            }
        }
    } else {
        //通过两端遍历查找确定
        while(i < j) {
            if(numbers[i] + numbers[j] == target) {
                sub_val = numbers[j];
                break;
            } else if(numbers[i] + numbers[j] < target) {
                i++;
            } else {
                j--;
            }
        }
    }
    for (j = 0; j < n; ++j) {
        if(tmp[j] == numbers[i] || tmp[j] == sub_val) {
            ans[0] = j+1;
            break;
        }
    }
    for (j++; j < n; ++j) {
        if(tmp[j] == numbers[i] || tmp[j] == sub_val) {
            ans[1] = j+1;
            break;
        }
    }
    return ans;
}