BZOJ2259 [Oibh]新型计算机

话说hzwer你在坑爹？、、、

我按照你的建图交了上去，发现WA。

开始检查= =。。。过了好久，突然觉得画风不对。。。hzwer您建图错了啊！！！

后来看了看zky的终于知道了怎么回事>_<

/**************************************************************
    Problem: 2259
    User: rausen
    Language: C++
    Result: Accepted
    Time:3220 ms
    Memory:52884 kb
****************************************************************/
 
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
 
using namespace std;
typedef long long ll;
const int N = 1000005;
const int M = 3000005;
 
int n, tot;
int dis[N], first[N];
bool vis[N], pre[N], nxt[N];
 
struct edges {
    int next, to, v;
    edges() {}
    edges(int _n, int _t, int _v) : next(_n), to(_t), v(_v) {}
} e[M];
 
struct heap_node {
    int v, to;
    heap_node() {}
    heap_node(int _v, int _to) : v(_v), to(_to) {}
 
    inline bool operator < (const heap_node &b) const {
        return v > b.v;
    }
};
 
priority_queue <heap_node> h;
 
inline int read() {
    int x = 0;
    char ch = getchar();
    while (ch < '0' || '9' < ch)
        ch = getchar();
    while ('0' <= ch && ch <= '9') {
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x;
}
 
void add_edge(int x, int y, int z) {
    e[++tot] = edges(first[x], y, z);
    first[x] = tot;
}
 
inline void add_to_heap(const int p) {
    for (int x = first[p]; x; x = e[x].next)
        if (dis[e[x].to] == -1)
            h.push(heap_node(e[x].v + dis[p], e[x].to));
}
 
void Dijkstra(int S) {
    memset(dis, -1, sizeof(dis));
    while (!h.empty()) h.pop();
    dis[S] = 0, add_to_heap(S);
    int p;
    while (!h.empty()) {
        if (dis[h.top().to] != -1) {
            h.pop();
            continue;
        }
        p = h.top().to;
        dis[p] = h.top().v;
        h.pop();
        add_to_heap(p);
    }
}
 
int main() {
    int i, j, x;
    n = read();
    for (i = 1; i <= n; ++i) {
        x = read();
        for (j = i + 1; j <= min(i + x + 1, n) && !pre[j]; ++j)
            pre[j] = 1, add_edge(j, j - 1, 1);
        for (j = i + x + 1; j <= n && !nxt[j]; ++j)
            nxt[j] = 1, add_edge(j, j + 1, 1);
        if (i + x <= n) add_edge(i, i + x + 1, 0);
        else add_edge(i, n + 1, i + x - n);
    }
    Dijkstra(1);
    printf("%d
", dis[n + 1]);
    return 0;
}