how can i find out a substring of minimum length having at least k times same character(for example k times a)of a string(please in C)
# | User | Rating |
---|---|---|
1 | tourist | 4009 |
2 | jiangly | 3831 |
3 | Radewoosh | 3646 |
4 | jqdai0815 | 3620 |
4 | Benq | 3620 |
6 | orzdevinwang | 3529 |
7 | ecnerwala | 3446 |
8 | Um_nik | 3396 |
9 | gamegame | 3386 |
10 | ksun48 | 3373 |
# | User | Contrib. |
---|---|---|
1 | cry | 164 |
1 | maomao90 | 164 |
3 | Um_nik | 163 |
4 | atcoder_official | 160 |
5 | -is-this-fft- | 158 |
6 | awoo | 157 |
7 | adamant | 156 |
8 | TheScrasse | 154 |
8 | nor | 154 |
10 | Dominater069 | 153 |
how can i find out a substring of minimum length having at least k times same character(for example k times a)of a string(please in C)
Name |
---|
Prefix sum the number of occurrences of character c. Then do the binary search for every s[i] and find prefix sum with biggest index j such that d[i]-d[j]>=k (if d[] is prefix sum). Answer is minimum of such i-j+1.
what is prefix sum please?
Prefix sum is array that for each prefix_sum[i] counts (in this case) number of character c from 0 (if string is 0-indexed) to i. How we do that, well prefix_sum[i]=prefix_sum[i-1]. And if s[i] is certain character that we want, increment prefix_sum[i] by 1.