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OI-codes/S2OJ/183/183.cpp

50 lines
905 B
C++

#include <bits/stdc++.h>
using namespace std;
int n, a[110], i;
bool t1, t2;
long long l = 0, r = 1000000000, mid, t[110], top;
bool check(long long x) {
top = 0;
for (i = 1; i < n; i++) {
if (a[i] == -1) {
t[++top] = x;
}
else if (a[i] > 0) {
t[++top] = a[i];
}
else if (top > 1) {
t[top - 1] += t[top];
top--;
}
}
return t[top] <= a[n];
}
int main() {
while (cin >> a[++n]) {}
n--;
t1 = check(0);
if (t[top] == a[n]) {
cout << 0 << endl;
return 0;
}
t2 = check(1000000001);
if (t1 == t2) {
cout << -1 << endl;
return 0;
}
while (l < r) {
mid = l + r + 1 >> 1;
if (check(mid)) {
l = mid;
}
else {
r = mid - 1;
}
}
cout << l << endl;
return 0;
}