830. Positions of Large Groups - C语言

最新推荐文章于 2019-05-03 22:39:00 发布

shirleylinyuer

最新推荐文章于 2019-05-03 22:39:00 发布

阅读量292

点赞数

CC 4.0 BY-SA版权

分类专栏： Coding

本文链接：https://blog.youkuaiyun.com/Shirleylinyuer/article/details/82920616

Coding 专栏收录该内容

11 篇文章

订阅专栏

本文介绍了一种算法，用于在小写字符串中定位长度为3或以上的连续相同字符组的起始和结束位置。通过一次遍历字符串并计数每个字符出现次数的方法，实现了对大型字符组的有效识别。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

830. Positions of Large Groups

In a string S of lowercase letters, these letters form consecutive groups of the same character.

For example, a string like S = "abbxxxxzyy" has the groups "a", "bb", "xxxx", "z" and "yy".

Call a group large if it has 3 or more characters. We would like the starting and ending positions of every large group.

The final answer should be in lexicographic order.

考察点：一个指针遍历S，一个指针记录每个字符出现的次数。注意返回值

My method:

/**
* Return an array of arrays of size *returnSize.
* The sizes of the arrays are returned as *columnSizes array.
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
*/
int** largeGroupPositions(char* S, int** columnSizes, int* returnSize) {
    int i = 0, j;
    int k = 0;
    int **ret = (int **)malloc(sizeof(int *) * 334);
    *columnSizes = (int *)malloc(sizeof(int) * 334);
    *returnSize = 0;

    while (S[i]) {
        j = i + 1;
        int ct = 1;
        char tmp = S[i];
        while (S[j] && (S[j] == tmp)) {
            ct++;
            j++;
        }
        if (ct >= 3) {
            (*columnSizes)[k] = 2;
            ret[k] = (int *)malloc(2 * sizeof(int));
            ret[k][0] = i;
            //printf("k=%d, ret[k][0]=%d\n", k, i);
            ret[k][1] = j - 1;
            //printf("k=%d, ret[k][1]=%d\n", k, j-1);
            k++;
            (*returnSize)++;
        }
        i = j;
    }
    return ret;
}