计蒜客_跳跃游戏二

BFS

#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
typedef pair<int, int> P;
int length[110];
int flag[110];
int n;

int bfs()
{
        priority_queue<P, vector<P>, greater<P> > q;
        fill(flag, flag + n, 0);
        q.push(P(0, 0));
        while (!q.empty()) {
                P p = q.top();
                q.pop();
                if (p.second == n - 1)  return p.first;
                for (int i = length[p.second]; i > 0; --i) {
                        if (!flag[p.second + i]) {
                                flag[p.second + i] = 1;
                                q.push(P(p.first + 1, p.second + i));
                        }
                }
        }
        return -1;
}

int main()
{
        while (cin >> n) {
                for (int i = 0; i < n; ++i) cin >> length[i];
                cout << bfs() << endl;
        }
        return 0;
}