LeetCode 1578.

package lc_1578;

/**
 * String ex = "bbbaaa";
 *         int[] time = new int[]{4,9,3,8,8,9};
 *         Solution sol = new Solution();
 *         System.out.println(sol.minCost(ex, time));
 */
public class Solution {
    public int minCost(String colors, int[] neededTime) {
        int last = 0, index = 0;
        int time = 0;
        last = colors.charAt(0);
        for (int i=1; i<colors.length(); i++){
            index = i;
            while (index < colors.length() && (int)colors.charAt(index) == last){
                index++;
            }
            if (index != i){
                time += returnSegTotal(i-1, index-1, neededTime);
                i = index - 1;
            }
            last = colors.charAt(i);
        }
        return time;
    }

    public int returnSegTotal(int from, int to, int[] neededTime){
        int max = 0, total = 0;
        for (int i=from; i<=to; i++){
            total += neededTime[i];
            if (max < neededTime[i]) max = neededTime[i];
        }
        return total - max;
    }
}