超级读入挂HDU（6044）

来源：互联网发布：js 函数对象的构造函数编辑：程序博客网时间：2024/04/30 05:45
#include <cstdio>#include <cstring>#include <algorithm>typedef long long LL;namespace fastIO {    #define BUF_SIZE 100000    //fread -> read    bool IOerror = 0;    inline char nc() {        static char buf[BUF_SIZE], *p1 = buf + BUF_SIZE, *pend = buf + BUF_SIZE;        if(p1 == pend) {            p1 = buf;            pend = buf + fread(buf, 1, BUF_SIZE, stdin);            if(pend == p1) {                IOerror = 1;                return -1;            }        }        return *p1++;    }    inline bool blank(char ch) {        return ch == ' ' || ch == '\n' || ch == '\r' || ch == '\t';    }    inline void read(int &x) {        char ch;        while(blank(ch = nc()));        if(IOerror)            return;        for(x = ch - '0'; (ch = nc()) >= '0' && ch <= '9'; x = x * 10 + ch - '0');    }    #undef BUF_SIZE};using namespace fastIO;const int maxn = 1000001, mod = 1000000007;int fact[maxn], iact[maxn];int n, l[maxn], r[maxn], ord[maxn], pL[maxn], pR[maxn], sz[maxn], tmp[maxn];int bfs(int rt){    int L = 0, R = 0;    static int que[maxn], f[maxn];    que[R++] = rt;    while(L < R)    {        int u = que[L++], vL = pL[u], vR = pR[u];        // [L, R] at x -> [L, x-1] [x+1, R]        if(l[u] == u)        {            if(vL != -1)                return 0;        }        else        {            if(vL == -1 || vL >= u || r[vL] != u - 1)                return 0;            que[R++] = vL;        }        if(u == r[u])        {            if(vR != -1)                return 0;        }        else        {            if(vR == -1 || vR <= u || l[vR] != u + 1)                return 0;            que[R++] = vR;        }    }    for(int i = n - 1; i >= 0; --i)    {        int u = que[i], ret = 1, szL, szR;        if(l[u] == u)            szL = 0;        else        {            ret = (LL)ret * f[pL[u]] % mod;            szL = sz[pL[u]];        }        if(u == r[u])            szR = 0;        else        {            ret = (LL)ret * f[pR[u]] % mod;            szR = sz[pR[u]];        }        if(szL && szR)            ret = (LL)ret * fact[szL + szR] % mod * iact[szL] % mod * iact[szR] % mod;        sz[u] = szL + szR + 1;        f[u] = ret;    }    return f[rt];}int main(){    iact[1] = 1;    for(int i = 2; i < maxn; ++i)        iact[i] = mod - (int)(mod / i * (LL)iact[mod % i] % mod);    fact[0] = iact[0] = 1;    for(int i = 1; i < maxn; ++i)    {        fact[i] = (LL)fact[i - 1] * i % mod;        iact[i] = (LL)iact[i - 1] * iact[i] % mod;    }    for(int Case = 1; read(n), !fastIO::IOerror; ++Case)    {        for(int i = 1; i <= n; ++i)            read(l[i]);        for(int i = 1; i <= n; ++i)            read(r[i]);        ord[0] = ord[n + 1] = 0;        int *cnt = sz;        memset(cnt + 1, 0, n * sizeof(int));        for(int i = 1; i <= n; ++i)            ++cnt[r[i]];        for(int i = 2; i <= n; ++i)            cnt[i] += cnt[i - 1];        for(int i = n; i >= 1; --i)            tmp[cnt[r[i]]--] = i;        memset(cnt + 1, 0, n * sizeof(int));        for(int i = 1; i <= n; ++i)            ++cnt[l[i]];        for(int i = 2; i <= n; ++i)            cnt[i] += cnt[i - 1];        for(int i = n; i >= 1; --i)            ord[cnt[l[tmp[i]]]--] = tmp[i];        for(int i = 1; i <= n; ++i)            pL[ord[i]] = l[ord[i - 1]] == l[ord[i]] ? ord[i - 1] : -1;        memset(cnt + 1, 0, n * sizeof(int));        for(int i = 1; i <= n; ++i)            ++cnt[l[i]];        for(int i = 2; i <= n; ++i)            cnt[i] += cnt[i - 1];        for(int i = n; i >= 1; --i)            tmp[cnt[l[i]]--] = i;        memset(cnt + 1, 0, n * sizeof(int));        for(int i = 1; i <= n; ++i)            ++cnt[r[i]];        for(int i = 2; i <= n; ++i)            cnt[i] += cnt[i - 1];        for(int i = n; i >= 1; --i)            ord[cnt[r[tmp[i]]]--] = tmp[i];        for(int i = 1; i <= n; ++i)            pR[ord[i]] = r[ord[i]] == r[ord[i + 1]] ? ord[i + 1] : -1;        int pos = -1;        for(int i = 1; i <= n; ++i)            if(l[i] == 1 && r[i] == n)            {                pos = i;                break;            }        printf("Case #%d: %d\n", Case, pos == -1 ? 0 : bfs(pos));    }    return 0;}
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