问题 G: 例题5-7 求圆周率pi的近似值

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;
int main(){
    double sum = 0.0;
    double sign = 1;
    for(double i =1; fabs(sign/i) > 1e-6; i += 2){
        sum += (sign/i);
        sign = -sign;
    }
    printf("PI=%.8lf\n",4.0 * sum);
}

问题 I: 习题5-10 分数序列求和

#include <iostream>
using namespace std;
int main(){
    int a=1, b=1;
    int t;
    double sum = 0.0;
    for(int i =1; i <=20;i ++){
         t= b;
         b= a+ b;
         a =t;
         sum +=(double)b/a;
         //cout << a << ' ' << b << ' '<< i << ' ' <<sum << endl;
    }
    printf("%.6lf\n",sum);
    //cout << a << ' ' << b << endl;
}

问题 A: 习题6-4 有序插入

#include <iostream>
using namespace std;
int main(){
    int a[10];
    for(int i = 0; i < 9 ; i ++){
        cin >> a[i];
    }
    int k;
    cin >> k;
    for(int i = 8; i >= 0 ; i --){
        if(a[i] > k){
            a[i+1] =a[i];
        }else{
            a[i+1]=k;
            break;
        }
    }
    for(int i = 0; i < 10 ; i ++){
        cout << a[i] << endl;
    }
}

问题 C: 习题6-6 杨辉三角

#include <iostream>
using namespace std;
int main(){
    int n; 
    cin >> n;
    int i, j, a[n][n];
    for(i =0; i < n; i ++){
        a[i][i] =1;
        a[i][0] =1;
    }
    for(i = 2; i < n; i ++){
        for(j=1; j<i; j ++){
            a[i][j] = a[i-1][j] + a[i-1][j-1];
        }
    }
    for(i = 0; i < n; i ++){
        for(j=0; j<=i; j ++){
            printf("%d ",a[i][j]);
        }
        cout << endl;
    }
}

问题 D: 习题6-12 解密

注意ascii码解密的转换

#include <iostream>
using namespace std;
int main(){
    string s;
    cin >> s;
    string res;
    for(auto c:s){
        if(c<='Z' && c >= 'A') res += 'A' + 'Z'-c;
        else if(  c<='z' && c >= 'a') res += 'a' + 'z'-c;
        else res +=c;
    }
    cout << res;
}

问题 E: 习题6-13 字符串比较

字符串比较需要直接叠加

#include <iostream>
#include <cstring>
using namespace std;
int main(){
    char s1[100], s2[100];
    scanf("%s",s1);
    scanf("\n%s",s2);
    int n = max(strlen(s1),strlen(s2));
    int ret=0;
    for(int i =0; i <n; i++){
        ret+= s1[i]-s2[i];
    }
    //printf("%s\n",s1);
    //printf("%s\n",s2);
    cout << ret;
}

#include <iostream>
#include <cstring>
using namespace std;
int main(){
    int a[20] ={1,1};
    printf("%d\n",a[0]);
    printf("%d\n",a[1]);
    for(int i =2;i < 20; i ++){
        a[i] = a[i-1] + a[i-2];
        printf("%d\n",a[i]);
    }
}

问题 B: C语言10.2

#include <iostream>
//#include <string>
#include <string.h>
using namespace std;
void swap(int *p1,int *p2){
    if(*p1 < *p2){
        int temp = *p1;
        *p1= *p2;
        *p2 = temp;
    }
}
int main(){
    int a, b ,c;
    cin >> a >> b >> c;
    swap(&a,&c);
    swap(&a,&b);
    swap(&b,&c);
    cout << a <<' '<<b << ' ' <<c << endl;
}

问题 C: C语言10.10

#include <iostream>
//#include <string>
#include <string.h>
using namespace std;
int main(){
    char *a = "I love China!";
    int n;
    cin >> n;
    a += n;
    puts(a);
}

问题 D: C语言10.15

#include <iostream>
//#include <string>
#include <string.h>
using namespace std;

void mini(char*p, char*q){
    if(strcmp(p,q) > 0){
        char x[20];
        //char *temp = x;
        strcpy(x, p);
        strcpy(p, q);
        strcpy(q, x);
    }
}


int main(){
    char s1[20], s2[20], s3[20];
    scanf("%s",s1);
    scanf("%s",s2);
    scanf("%s",s3);
    mini(s1,s2);
    mini(s1,s3);
    mini(s2,s3);
    cout << s1 << endl;
    cout << s2 << endl;
    cout << s3 << endl;

    return 0;
}

问题 E: C语言10.16

#include <iostream>

using namespace std;

void input(int *num){
    for(int i = 0 ; i < 10; i ++){
        scanf("%d",&num[i]);
    }
}


void proc(int *num){
    int max = num[9];
    int min = num[0];
    int maxi;
    int mini;
    for(int i=1; i < 10; i ++){
        if(num[i] > max){
            max = num[i];
            maxi = i;
        }

        if(num[i] < min){
            min = num[i];
            mini = i;
        }
    }

    int temp;
    temp = num[9];
    num[9] = num[maxi];
    num[maxi] = temp;
    int temp1;
    temp1 = num[0];
    num[0] = num[mini];
    num[mini] = temp1;
}

void output(int *num){
    for(int i = 0; i < 10; i ++){
        printf("%d ", num[i]);
    }

    printf("\n");
}



int main(){
    int a[10];
    int *num = a;
    input(num);
    proc(num);
    output(num);

    return 0;
}

问题 D: C语言11.7

#include <iostream>
#include <vector>

using namespace std;

struct person{
    int num;
    char name[10];
    char sex;
    char job;
    union {
        int clas;
        char position[10];
    }category;
};


int main(){
    int n;
    cin >> n;
    vector<person> per(n);
    for(int i = 0; i < n; i ++){
        scanf("%d %s %c %c", &per[i].num, per[i].name, &per[i].sex, &per[i].job);
        if(per[i].job == 's'){
            scanf("%d",&per[i].category.clas);
        }
        if(per[i].job == 't'){
            scanf("%s",per[i].category.position);
        }
    }
    for(int i =0; i < n; i ++){
        if(per[i].job == 's'){
            printf("%d %s %c %c %d\n", per[i].num, per[i].name, per[i].sex, per[i].job,per[i].category.clas);
        }
        if(per[i].job == 't'){
            printf("%d %s %c %c %s\n", per[i].num, per[i].name, per[i].sex, per[i].job,per[i].category.position);
        }    
    }
}

问题 D: C语言11.7

#include<stdio.h>

struct student{

         int id;

         char name[20];

         int c1,c2,c3;

}stu[5];

void input(){

         int n=5;

         for(int i=0;i<n;i++){

                   scanf("%d %s %d %d %d",&stu[i].id,stu[i].name,&stu[i].c1,&stu[i].c2,&stu[i].c3);

         }       

}

void print(){

         int n=5;

         for(int i=0;i<n;i++){

                   printf("%d %s %d %d %d\n",stu[i].id,stu[i].name,stu[i].c1,stu[i].c2,stu[i].c3);

         }

}

int main(){

         input();

         print();

         return 0;

}

问题 E: C语言11.8

#include <iostream>
#include <vector>

using namespace std;

struct student{
    int id;
    char name[20];
    int c1, c2, c3;


}stu[10];


int main(){
    int n = 10;
    double cnt1 = 0, cnt2 = 0, cnt3 = 0;
    int average[19];

    for(int i = 0 ; i < n; i ++){
        scanf("%d %s %d %d %d", &stu[i].id, stu[i].name, &stu[i].c1, &stu[i].c2, &stu[i].c3);
        cnt1 += stu[i].c1;
        cnt2 += stu[i].c2;
        cnt3 += stu[i].c3;
        average[i] = (stu[i].c1 + stu[i].c2 + stu[i].c3)/3;
    }

    cnt1 /=10.0;
    cnt2 /=10.0;
    cnt3 /=10.0;

    int max = 0;
    int i, k;
    for (i = 0;i < 10; i ++){
        if (average[i] > max){
            max = average[i];
            k = i;
        }
    }
    printf("%.2lf %.2lf %.2lf\n", cnt1, cnt2, cnt3);
    printf("%d %s %d %d %d", stu[k].id, stu[k].name, stu[k].c1, stu[k].c2, stu[k].c3);

}

[PA T B1001]害死人不偿命的（3n+l）猜想

#include <iostream>

using namespace std;

int main(){
    int n, step = 0;
    scanf("%d",&n);
    while(n  != 1){
        if(n % 2 == 0) n = n /2;
        else n = (3 *n + 1)  /2;
        step ++;
    }

    printf("%d\n", step);

    return 0;
}

算法题 _Acw_Leetcode_等

算法笔记

问题 G: 例题5-7 求圆周率pi的近似值

问题 I: 习题5-10 分数序列求和

问题 A: 习题6-4 有序插入

问题 C: 习题6-6 杨辉三角

问题 D: 习题6-12 解密

问题 E: 习题6-13 字符串比较

问题 B: C语言10.2

问题 C: C语言10.10

问题 D: C语言10.15

问题 E: C语言10.16

问题 D: C语言11.7

问题 D: C语言11.7

问题 E: C语言11.8