HDU 5200/BC 36 C Trees

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其实没有官方题解说的那么麻烦(＞﹏＜) 直接离线处理后开个数组模拟下即可

砍当前树时当左右的树被砍掉时 ans就--

都没被砍掉 ans就++

#include<iostream>#include<cstdio>#include<cstring>#include<cctype>#include<cmath>#include<vector>#include<queue>#include<map>#include<algorithm>#include<set>#define scnaf scanf#define cahr char#define bug puts("bugbugbug");using namespace std;typedef long long ll;typedef unsigned long long ull;typedef pair<int,int> pii;const int mod=1000000007;const int maxn=5e4+100;const int inf=1e9;inline void RDF(int &ret) { //输入为负数    char c;    int sgn;    while(c != '-' && (c < '0' || c > '9')) c = getchar();    sgn = (c == '-') ? -1 : 1;    ret = (c == '-') ? 0 : (c - '0');    while(c = getchar(), c >= '0' && c <= '9') ret = ret * 10 + (c - '0');    ret *= sgn;}inline void RD(int &ret) { //输入为整数    char c;    do {        c = getchar();    } while(c < '0' || c > '9');    ret = c - '0';    while((c = getchar()) >= '0' && c <= '9') {        ret = ret * 10 + (c - '0');    }}inline void OT(int a) { //输出为正数    if(a >= 10) {        OT(a / 10);    }    putchar(a % 10 + '0');}struct T{    int h,id;    bool operator < (const T &b) const {        return h<b.h;    }}a[maxn],q[maxn];int tree[maxn],ans[maxn];int main(){    int n,Q;    while(~scanf("%d%d",&n,&Q))    {        tree[0]=tree[n+1]=-1;        for(int i=0;i<n;i++)        {            RD(a[i].h);            a[i].id=i+1;            tree[i+1]=1;        }        sort(a,a+n);        for(int i=0;i<Q;i++)        {            RD(q[i].h);            q[i].id=i;        }        sort(q,q+Q);        int cnt=0,anss=1;        for(int i=0;i<Q;i++)        {            while(cnt<n&&a[cnt].h<=q[i].h)            {                int now=a[cnt].id;                tree[now]=-1;                if(tree[now-1]==tree[now+1])                    if(tree[now-1]==-1) anss--;                    else anss++;                cnt++;            }            ans[q[i].id]=anss;        }        for(int i=0;i<Q;i++)        {            //cout<<ans[i]<<endl;           OT(ans[i]);puts("");        }    }}

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