2009 3b

public int getChargeStartTime(int chargeTime){
    int startTime = 0;
    for (int i = 1; i < 24; i++){
        if (this.getChargingCost(i, chargeTime) < this.getChargingCost(startTime, chargeTime)){
            startTime = i;
        }
    }
    
    return startTime;
}

2017 1b

public boolean isStrictlyIncreasing(){
    for (int i = 0; i < digitList.size()-1; i++){
        if (digitList.get(i).intValue() >= digitList.get(i+1).intValue()){
            return false;
        }
    }
    
    return true;
}

2019 3b

public boolean evaluateLight(int row, int col) {
    int onInCol = 0;
    for (int r = 0; r < lights.length; r++) {
        if (lights[r][col]) {
            onInCol++;
        }
    }
    
    if (lights[row][col] && onInCol % 2 == 0) {
        return false;
    } else if (!lights[row][col] && onInCol % 3 == 0) {
        return true;
    } else {
        return lights[row][col];
    }
}