第十四届蓝桥杯集训——练习解题阶段(无序阶段)-ALGO-965 进击的青蛙

#include<stdio.h>
//const int N = 1e6+5;
typedef long long LL;//long long
LL dp[1000000], n;
int main()
{
//  cin >> n;
 int i;
  scanf("%d",&n);
  for (  i = 1; i <= n; ++i ) {
  //  cin >> dp[i];
   scanf("%d",&dp[i]);
  }
    //初始值：
/*  dp[1] == 0 ? dp[1] = 1 : dp[1] = 0;
  dp[2] == 0 ? dp[2] = dp[1] + 1 : dp[2] = 0;
  dp[3] == 0 ? dp[3] = dp[1] + dp[2] + 1 : dp[3] =0;*/
  if(dp[1]==0)dp[1]=1;else dp[1]=0;
    if(dp[2]==0)dp[2]=dp[1]+1;else dp[2]=0;
    if(dp[3]==0)dp[3]=dp[1]+dp[2]+1;else dp[3]=0;
  
    //dp[i] = dp[i-1] + dp[i-2] + dp[i-3];
  for (  i = 4; i <= n; ++i ) {
    if ( dp[i] == 1 ) dp[i] = 0;
    else {
      dp[i] = (dp[i-1] % 1000000007 + dp[i-2] % 1000000007 +dp[i-3] % 1000000007 ) % 1000000007;
    }
  }
  
    //当dp[n] == 0的时候，就是跳不到n这个点
  if ( !dp[n] ) //cout << "No Way!\n";
  printf("No Way!\n");
    //跳的到
  else //cout << dp[n] << '\n';
  printf("%d\n",dp[n]); 
  
  return 0;
}

#include<stdio.h>
#include<stdlib.h>
int main(){
  int n, key;
  long long a[4];
  scanf("%d", &n);
  for(int i = 0; i < 2; i++){
    a[i] = 0;
  }
  a[2] = 1;
  for(int i = 0; i < n; i++){
    scanf("%d", &key);
    if(key == 0){
      a[3] = (a[0] + a[1] + a[2]) % 1000000007;
    }
    else{
      a[3] = 0;
    }
    for(int j = 0; j < 3; j++){
      a[j] = a[j+1];
    }
  }
  if(a[3] == 0){
    printf("No Way!");
  }
  else{
    printf("%lld",a[3]);
  }
  return 0;
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
public class Main { 
  public static void main(String[] args) throws IOException {
    StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
    in.nextToken();
    int n =(int)in.nval;
    long m[] = new long[n];
    for(int i=0;i<n;i++) {
      in.nextToken();
      m[i]=(int)in.nval;
    }
    if(m[n-1]==1||(m[n-2]==1&&m[n-3]==1&&m[n-4]==1)) {
      System.out.println("No Way!");
    }else {
      long x =nextway(m);
      System.out.println(x);
    }
  } 
  public static long nextway(long[] m) {
    int x = m.length;
    long dp[] = new long[x];
    for(int i=0;i<x;i++) {
      if(i<3) {
        if(m[i]==0&&i==0) {
          dp[i]=1;
        }else if(m[i]==0&&i==1) {
          dp[i]=dp[i-1]+1;
        }else if(m[i]==0&&i==2) {
          dp[i]=dp[i-1]+dp[i-2]+1;
        }else {
          dp[i]=0;
        }
      }else {
        if(m[i]==1) {
          dp[i]=0;
        }else {
          dp[i]= (dp[i - 1] % 1000000007 + dp[i - 2] % 1000000007 + dp[i - 3] % 1000000007) % 1000000007;
        }
      }
    }
    return dp[x-1];
  }
}

mask=1000000007
n=int(input())
bridge=[]
for i in range(3):
    bridge.append(int(input()))
if bridge[0]!=1:
    temp1=1
    if bridge[1]!=1:
        temp2=2
        if bridge[2]!=1:
            temp_n=4
        else:
            temp_n=0
    else:
        temp2=0
        if bridge[2]!=1:
            temp_n=2
        else:
            temp_n=0
else:
    temp1=0
    if bridge[1]!=1:
        temp2=1
        if bridge[2]!=1:
            temp_n=2
        else:
            temp_n=0
    else:
        temp2=0
        if bridge[2]!=1:
            temp_n=1
        else:
            temp_n=0
for i in range(3,n):
    temp0,temp1,temp2=temp1,temp2,temp_n
    if input()!='1':
        temp_n=(temp0+temp1+temp2)%mask
    else:
        temp_n=0
if temp_n!=0:
    print(temp_n)
else:
    print("No Way!")