import time


class TimeStamp:
    keys: [str]
    values: [int]
    total: int

    def __init__(self):
        self.keys = []
        self.values = []
        self.total = 0

    def save(self, key: str):
        tm = time.time()
        self.keys.append(key)
        self.values.append(tm)

    def info(self):
        lastKey = None
        lastValue = None
        msg: [str] = []
        for i in enumerate(self.keys):
            k = self.keys[i[0]]
            v = self.values[i[0]]
            if lastValue is None:
                lastKey = k
                lastValue = v
            else:
                use = round(v - lastValue, 4)
                msg.append(k + " -> " + lastKey + " use " + str(use))
                lastKey = k
                lastValue = v
                self.total += use
        msg.append("total: " + str(self.total))
        for s in msg:
            print(s)