Solution.java

class Solution {
    public int canCompleteCircuit(int[] gas, int[] cost) {
        int min = Integer.MAX_VALUE;
        int start = -1;
        
        int current = 0;
        for (int i = 0; i < gas.length; i++) {
            current += gas[i] - cost[i];
            if (current < min) {
                min = current;
                start = i + 1;
            }
        }
        
        if (start == -1) {
            return -1;
        }
        
        // System.out.println("min = " + min + " start = " + start);
        
        current = 0;
        for (int i = start; i < gas.length; i++) {
            current += gas[i] - cost[i];
            if (current < 0) {
                return -1;
            }
        }
        
        for (int i = 0; i < start; i++) {
            current += gas[i] - cost[i];
            if (current < 0) {
                return -1;
            }
        }
        
        return start == gas.length ? 0 : start;
    }
}