题目

kedaOJ#P2849时间涟漪

思路

栈

代码

#include<bits/stdc++.h>
using namespace std;
int main() {
    int N;
    cin >> N;
    stack<int> timeRipples;
    int maxEnergy = INT_MIN;
    for (int i = 0; i < N; ++i) {
        int instruction;
        cin >> instruction;
        if (instruction == 1) {
            int energy;
            cin >> energy;
            timeRipples.push(energy);
            if (energy > maxEnergy) {
                maxEnergy = energy;
            }
        } else if (instruction == 2) {
            if (!timeRipples.empty()) {
                int topEnergy = timeRipples.top();
                timeRipples.pop();
                if (topEnergy == maxEnergy) {
                    // 重新计算最大能量
                    maxEnergy = INT_MIN;
                    stack<int> tempStack;
                    while (!timeRipples.empty()) {
                        int energy = timeRipples.top();
                        timeRipples.pop();
                        tempStack.push(energy);
                        if (energy > maxEnergy) {
                            maxEnergy = energy;
                        }
                    }
                    while (!tempStack.empty()) {
                        timeRipples.push(tempStack.top());
                        tempStack.pop();
                    }
                }
            }
        } else if (instruction == 3) {
            if (!timeRipples.empty()) {
                cout << maxEnergy << endl;
            } else {
                cout << 0 << endl;
            }
        }
    }
}