Question
Example 1:
Input: "00110011"
Output: 6
Explanation: There are 6 substrings that have equal number of consecutive 1's and 0's: "0011", "01", "1100", "10", "0011", and "01".
Notice that some of these substrings repeat and are counted the number of times they occur.
Also, "00110011" is not a valid substring because all the 0's (and 1's) are not grouped together.
Example 2:
Input: "10101"
Output: 4
Explanation: There are 4 substrings: "10", "01", "10", "01" that have equal number of consecutive 1's and 0's.
Solution
思路:题目大意是,给一个二进制的字符串,问有多少子串的0个数量等于1的数量且子串中0和1不能交替出现。
00110011
zeroCount oneCount last
0 1 0 -1->0
0 2 0 0
1 2 1 0->1 有一个符合要求的子串01
1 2 2 1 有一个符合要求的子串0011
0 1 2 1->0 有一个符合要求的子串10
0 2 2 0 有一个符合要求的子串1100
1 2 1 0->1 有一个符合要求的子串01
1 2 2 1 有一个符合要求的子串0011
Java实现:
public int countBinarySubstrings(String s) {
// 子串满足
// 1)0和1个数相等
// 2)0与1不能交替出现
int ans = 0;
int zeroCount = 0;
int oneCount = 0;
int last = -1;
for (int i=0; i<s.length(); i++) {
char c = s.charAt(i);
if (c == '0') {
if (last == -1 || last == 1) {
zeroCount = 0;
last = 0;
}
zeroCount++;
} else {
if (last == -1 || last == 0) {
oneCount = 0;
last = 1;
}
oneCount++;
}
if (last == 0) ans += zeroCount<=oneCount?1:0;
else ans += oneCount<=zeroCount?1:0;
}
return ans;
}
原文地址:https://www.cnblogs.com/okokabcd/p/9245719.html
时间: 2024-11-05 19:37:28