Formatted question description: https://leetcode.ca/all/1422.html
1422. Maximum Score After Splitting a String (Easy)
Given a string s
of zeros and ones, return the maximum score after splitting the string into two non-empty substrings (i.e. left substring and right substring).
The score after splitting a string is the number of zeros in the left substring plus the number of ones in the right substring.
Example 1:
Input: s = "011101" Output: 5 Explanation: All possible ways of splitting s into two non-empty substrings are: left = "0" and right = "11101", score = 1 + 4 = 5 left = "01" and right = "1101", score = 1 + 3 = 4 left = "011" and right = "101", score = 1 + 2 = 3 left = "0111" and right = "01", score = 1 + 1 = 2 left = "01110" and right = "1", score = 2 + 1 = 3
Example 2:
Input: s = "00111" Output: 5 Explanation: When left = "00" and right = "111", we get the maximum score = 2 + 3 = 5
Example 3:
Input: s = "1111" Output: 3
Constraints:
2 <= s.length <= 500
- The string
s
consists of characters '0' and '1' only.
Related Topics:
String
Solution 1.
zero
and one
are the counts of 0
s in left
and 1
s in right
.
First compute the count of all 1
s as one
. Then for each i
in range [0, N - 2]
, increment zero
if s[i] == '0'
and decrement one
if s[i] == '1'
. The maximum zero + one
is the result.
// OJ: https://leetcode.com/problems/maximum-score-after-splitting-a-string
// Time: O(N)
// Space: O(1)
class Solution {
public:
int maxScore(string s) {
int one = 0, zero = 0, ans = 0;
for (char c : s) one += c == '1';
for (int i = 0; i < s.size() - 1; ++i) {
char c = s[i];
zero += c == '0';
one -= c == '1';
ans = max(ans, zero + one);
}
return ans;
}
};
Java
class Solution {
public int maxScore(String s) {
int length = s.length();
int ones = 0;
for (int i = 0; i < length; i++) {
char c = s.charAt(i);
if (c == '1')
ones++;
}
int maxScore = 0;
int leftZeros = 0, rightOnes = ones;
for (int i = 1; i < length; i++) {
char lastC = s.charAt(i - 1);
if (lastC == '0')
leftZeros++;
else
rightOnes--;
int score = leftZeros + rightOnes;
maxScore = Math.max(maxScore, score);
}
return maxScore;
}
}