Bulb Switcher IV
Difficulty:Medium
Problem
There is a room with n bulbs, numbered from 0 to n-1, arranged in a row from left to right. Initially all the bulbs are turned off.
Your task is to obtain the configuration represented by target where target[i] is '1' if the i-th bulb is turned on and is '0' if it is turned off.
You have a switch to flip the state of the bulb, a flip operation is defined as follows:
Choose any bulb (index i) of your current configuration.
Flip each bulb from index i to n-1.
When any bulb is flipped it means that if it is 0 it changes to 1 and if it is 1 it changes to 0.
Return the minimum number of flips required to form target.
Example 1:
Input: target = "10111"
Output: 3
Explanation: Initial configuration "00000".
flip from the third bulb: "00000" -> "00111"
flip from the first bulb: "00111" -> "11000"
flip from the second bulb: "11000" -> "10111"
We need at least 3 flip operations to form target.
Example 2:
Input: target = "101"
Output: 3
Explanation: "000" -> "111" -> "100" -> "101".
Example 3:
Input: target = "00000"
Output: 0
Example 4:
Input: target = "001011101"
Output: 5
Constraints:
1 <= target.length <= 10^5
target[i] == '0' or target[i] == '1'
Recommended: Please try your approach on your integrated development environment (IDE) first, before moving on to the solution.
Few words from CodingHumans : Don't Just copy paste the solution, try to analyze the problem and solve it without looking by taking the the solution as a hint or a reference . Your understanding of the solution matters.
HAPPY CODING 😁
Solution:
( Java )
class Solution {
public:
int minFlips(string s) {
int n = s.size(), L = 0;
for (; L < n && s[L] == '0'; ++L);
if (L == n) return 0;
int ret = 0;
for (int i = L, j; i < n; i = j) {
for (j = i + 1; j < n && s[j] == s[i]; ++j);
++ret;
}
return ret;
}
};
Solution:
( Python )
class Solution(object):
def minFlips(self, target):
flip = ans = 0
for c in target:
c = int(c)
if c ^ flip:
ans += 1
flip ^= 1
return ans
If you have any doubts regarding this problem or need the solution in other programming languages then leave a comment down below .
