UVA - 442矩阵链乘

版权声明：博主的博客不值钱随便转载但要注明出处 https://blog.csdn.net/easylovecsdn/article/details/86664330

栈模拟即可，模的我一阵酸爽，多亏vs2017强大的调试。

Code

#include <bits/stdc++.h>
#define MAX 30
using namespace std;
typedef long long LL;
struct Node {
	int x, y;
	Node() {}
	Node(int xx, int yy) {
		x = xx;
		y = yy;
	}
};
Node a[MAX];
stack<Node> s;
int main()
{
	char c;
	int n, x, y;
	LL res;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> c >> x >> y;
		getchar();
		a[c - 'A'].x = x;
		a[c - 'A'].y = y;
	}
	res = 0;
	while ((c = getchar()) != EOF) {
		
		if (c == '\n') {
			if (res == -1)
				cout << "error" << endl;
			else
				cout << res << endl;
			while (!s.empty())
				s.pop();
			res = 0;
			continue;
		}
		if (c == '(') s.push(Node(-1, 0));
		else if (c == ')') {
			int xx = s.top().x;
			int yy = s.top().y;
			s.pop();
			while (xx != -1) {  //代表括号"("
				Node t = s.top();
				s.pop();
				if (t.x == -1) break;
				if (t.y != xx) res = -1;  //error
				if (res == -1) continue;
				res += xx * yy * t.x;
				xx = t.x;
				//yy = t.y;
			}
			s.push(Node(xx, yy));
		}
		else s.push(Node(a[c - 'A'].x, a[c - 'A'].y));
	}
	return 0;
}