contest 1.23

A.骰子

规律

#include <iostream>
#include<cstdio>
typedef long long ll;
using namespace std;

ll dp[5][100005],sum[5][100005];

ll n,m;
void init(){
  dp[1][1]=1,dp[1][2]=5,dp[1][3]=6,dp[1][4]=2;
  for(ll i=1;i<=n;i++){
    ll tmp=i%4;
    if(tmp==0) tmp=4;
    dp[1][i]=dp[1][tmp];
    sum[1][i]=sum[1][i-1]+dp[1][i];
  }
  dp[2][1]=5,dp[2][2]=6,dp[2][3]=8;
  dp[2][4]=9;dp[2][5]=8;dp[2][6]=6;
  for(ll i=1;i<=n;i++){
    ll tmp=i%6;
    if(tmp==0) tmp=6;
    dp[2][i]=dp[2][tmp];
    sum[2][i]=sum[2][i-1]+dp[2][i];
  }
  dp[3][1]=11;
  for(ll i=1;i<=n;i++){
    ll tmp=i%1;
    if(tmp==0) tmp=1;
    dp[3][i]=dp[3][tmp];
    sum[3][i]=sum[3][i-1]+dp[3][i];
  }
  dp[4][1]=14;
  for(ll i=1;i<=n;i++){
    ll tmp=i%1;
    if(tmp==0) tmp=1;
    dp[4][i]=dp[4][tmp];
    sum[4][i]=sum[4][i-1]+dp[4][i];
  }
}

int main()
{
    scanf("%lld%lld",&n,&m);
    init();
    ll x=m/4;
    ll r=m%4;
    ll ans=sum[4][n]*x;
    if(r) ans+=sum[r][n];
    printf("%lld
",ans);
    return 0;
}

D.zzs妹子

排序+优先队列

#include <iostream>
#include<cstdio>
#include<queue>
#include<algorithm>
using namespace std;

struct Node{
    int l,r;
    bool operator <(const Node& b)const{
      return r>b.r;
    }
}node[200005];
priority_queue<Node> q;

bool cmp(Node a,Node b){
  if(a.l!=b.l) return a.l<b.l;
  else return a.r<b.r;
}

int main()
{
    int n;scanf("%d",&n);
    for(int i=1;i<=n;i++){
        scanf("%d%d",&node[i].l,&node[i].r);
    }
    sort(node+1,node+1+n,cmp);
    int ans=0;
    for(int i=1;i<=n;i++){
        if(q.empty()) {ans++;q.push(node[i]);continue;}
        Node top=q.top();
        if(node[i].l>top.r) {q.pop();q.push(node[i]);}
        else {ans++;q.push(node[i]);}
    }
    printf("%d
",ans);
    return 0;
}

B.子序列 II

树状数组

#include <iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#define mod 1000000007
#define lowbit(x) x&(-x)
typedef long long ll;
using namespace std;

ll n,t;
ll a[200005],b[200005],c[200005];
ll pre_smaller[200005],pre_bigger[200005];
ll after_smaller[200005],after_bigger[200005];

inline ll getid(ll x){return lower_bound(b+1,b+1+t,x)-b;}

void add(ll pos,ll val){
  for(ll i=pos;i<=n;i+=lowbit(i)) c[i]+=val;
}

ll getsum(ll pos){
  ll ret=0;
  for(ll i=pos;i>0;i-=lowbit(i)) ret+=c[i];
  return ret;
}

int main()
{
    scanf("%lld",&n);
    for(ll i=1;i<=n;i++) scanf("%lld",&a[i]),b[i]=a[i];
    sort(b+1,b+1+n);
    t=unique(b+1,b+1+n)-(b+1);
    for(ll i=1;i<=n;i++){
        ll id=getid(a[i]);
        add(id,1);
        pre_smaller[i]=getsum(id-1);
        pre_bigger[i]=i-getsum(id);
    }
    memset(c,0,sizeof(c));
    for(ll i=n;i>=1;i--){
        ll id=getid(a[i]);
        add(id,1);
        after_smaller[i]=getsum(id-1);
        after_bigger[i]=(n-i+1)-getsum(id);
    }
    ll ans=0;
    for(ll i=1;i<=n;i++){
        ans=(ans+pre_smaller[i]*after_bigger[i]%mod)%mod;
        ans=(ans+pre_bigger[i]*after_smaller[i]%mod)%mod;
    }
    ans=ans%mod;
    printf("%lld
",ans);
    return 0;
}

A.冠军剑士

bfs

#include <iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#define inf 0x3f3f3f3f
typedef long long ll;
using namespace std;
 
ll m,n,x1,y1,x2,y2,k;
ll Map[105][105];
ll vis[105][105];
ll dire[4][2]={0,-1,-1,0,0,1,1,0};
struct Node{ll x,y,dis;};
 
void setbomb(ll x,ll y){
  for(ll i=max(x-1,(ll)1);i<=min(x+1,n);i++){
    for(ll j=max(y-1,(ll)1);j<=min(y+1,m);j++){
        Map[i][j]=-1;
    }
  }
}
 
bool in(ll x,ll y){
 return x>=1&&x<=n&&y>=1&&y<=m;
}
 
ll bfs(ll x,ll y){
  queue<Node> q;
  while(!q.empty()) q.pop();
  q.push(Node{x,y,0});vis[x][y]=1;
  while(!q.empty()){
    Node now=q.front();q.pop();
    if(now.x==x2&&now.y==y2) return now.dis;
    for(ll i=0;i<4;i++){
        ll nx=now.x+dire[i][0];
        ll ny=now.y+dire[i][1];
        if(in(nx,ny)&&!vis[nx][ny]&&Map[nx][ny]!=-1){
            q.push(Node{nx,ny,now.dis+1});
            vis[nx][ny]=1;
        }
    }
  }
  return 0;
}
 
int main()
{
    scanf("%lld%lld%lld%lld%lld%lld%lld",&m,&n,&x1,&y1,&x2,&y2,&k);
    swap(n,m);
    for(ll i=1;i<=k;i++){
        ll x,y;scanf("%lld%lld",&x,&y);
        setbomb(x,y);
    }
    ll ans=bfs(x1,y1);
    printf("%lld
",ans);
    return 0;
}

C.新校游乐场

01背包

#include <iostream>
#include<cstdio>
using namespace std;
 
int n,t;
int v[1005],w[1005],dp[1005];
 
int main()
{
    scanf("%d%d",&n,&t);
    for(int i=1;i<=n;i++){
        scanf("%d%d",&v[i],&w[i]);
    }
    for(int i=1;i<=n;i++){
        for(int j=t;j>=w[i];j--){
            dp[j]=max(dp[j],dp[j-w[i]]+v[i]);
        }
    }
    printf("%d
",dp[t]);
    return 0;
}

B.帝国交通