3.1简单模拟

自己写的题解

#include <stdio.h>
#include <stdlib.h>
int main() {int N;int num=0;scanf("%d",&N);while(N!=1){if(N%2==0){N=N/2;}else{N=(3*N+1)/2;}num++;}printf("%d",num);system("pause"); // 防止运行后自动退出，需头文件stdlib.hreturn 0;
}

标答

#include <stdio.h>
#include <stdlib.h>
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);system("pause"); // 防止运行后自动退出，需头文件stdlib.hreturn 0;
}

3.2查找元素

自己写的题解

#include <stdio.h>
#include <stdlib.h>
int main() {int n;int f=0;int a[100000];scanf("%d",&n);for(int i=0;i<n;i++){scanf("%d",&a[i]);}scanf("%d",&f);int find=-1;for(int i=0;i<n;i++){if(a[i]==f){find=i+1;}}if(find!=-1)printf("%d\n",find);elseprintf("NO");system("pause"); // 防止运行后自动退出，需头文件stdlib.hreturn 0;
}

标答

#include <cstdio>
const int MAXN = 20;
int a[MAXN];
int main() {int n, x;scanf("%d", &n);for (int i = 0; i < n; i++) {scanf("%d", &a[i]);}int position = -1;              // 待查找元素的下标，-1表示找不到scanf("%d", &x);for (int i = 0; i < n; i++) {   // 遍历序列if (a[i] == x) {            // 如果当前元素就是待查找的元素position = i + 1;       // 记录下标，注意要加1break;                  // 不需要继续查找了，退出循环}}if (position == -1) {           // 如果找不到printf("NO");               // 输出NO} else {                        // 如果能找到printf("%d", position);     // 输出对应的下标}return 0;
}

3.3图形输出

自己写的题解

#include <stdio.h>
#include <stdlib.h>
int main() {int row=0;scanf("%d",&row);int col=row;for(int i=0;i<row-1;i++){printf("*");for(int j=0;j<i+1;j++){if(i==j&&j!=0){printf("*");}else if(j!=0)printf(" ");}printf("\n");}for(int i=0;i<row;i++){printf("*");}system("pause"); // 防止运行后自动退出，需头文件stdlib.hreturn 0;
}

标答1

#include <cstdio>int main() {int n;scanf("%d", &n);printf("*\n");for (int i = 0; i < n - 2; i++) {printf("*");for (int j = 1; j <= i; j++) {printf(" ");}printf("*\n");}for (int i = 0; i < n; i++) {printf("*");}return 0;
}

标答2

#include <cstdio>
#include <cstring>
const int MAXN = 100;
char s[MAXN][MAXN + 1];int main() {int n;scanf("%d", &n);memset(s, ' ', sizeof(s));for (int i = 0; i < n - 1; i++) {s[i][0] = s[i][i] = '*';s[i][i + 1] = '\0';printf("%s\n", s[i]);}for (int i = 0; i < n; i++) {printf("*");}return 0;
}

3.4日期处理

 

标答

#include <cstdio>bool isLeapYear(int year) {return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
}int main() {int year;scanf("%d", &year);printf(isLeapYear(year) ? "YES" : "NO");return 0;
}

标答

#include <cstdio>
// 每个月的天数
int dayOfMonth[2][13] = {{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
// 是否是闰年
bool isLeapYear(int year) {return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
}
// 给当前日期加1天（注意参数都用了引用&，这样对参数的修改可以同步到函数外）
void addOneDay(int &year, int &month, int &day) {day++;                    // 让day加1if (day > dayOfMonth[isLeapYear(year)][month]) {  // 如果超过当前月的天数month++;              // 让month加1day = 1;              // 重置day为1号}if (month > 12) {         // 如果月份大于12year++;               // 让year加1month = 1;            // 重置month为1月}
}int main() {int year, month, day, n;scanf("%d-%d-%d", &year, &month, &day);       // 按格式输入年月日scanf("%d", &n);                              // 输入需要增加的天数for (int i = 0; i < n; i++) {                 // 遍历n次，每次加1天addOneDay(year, month, day);}printf("%04d-%02d-%02d", year, month, day);   // 按格式输出年月日return 0;
}

3.5进制转换

自己写的题解

#include <stdio.h>
#include <stdlib.h>
int main() {int y=0;scanf("%d",&y);int z[40],num=0;do{z[num++]=y%2;y=y/2;}while(y!=0);for(int i=num-1;i>=0;i--){printf("%d",z[i]);}system("pause"); // 防止运行后自动退出，需头文件stdlib.hreturn 0;
}

公式：将十进制数y转换为Q进制数z

int z[40],num=0;do{z[num++]=y%Q;y=y/Q;}while(y!=0);

自己写的题解

#include <stdio.h>
#include <stdlib.h>
int main() {int y=0,product=1;int x=0;scanf("%d",&x);while(x!=0){y=y+(x%10)*product;x=x/10;product=product*2;}printf("%d",y);system("pause"); // 防止运行后自动退出，需头文件stdlib.hreturn 0;
}

公式：将P进制数x转换为十进制数y

int y=0,product=1;while(x!=0){y=y+(x%10)*product;x=x/10;product=product*P;}

3.6字符串处理

标答

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
const int maxn=50;
int judge(char str[]){int len=strlen(str);for(int i=0;i<len/2;i++){if(str[i]!=str[len-1-i]){return 0;}}return 1;
}
int main() {char str[maxn];while(scanf("%s",str)!=EOF){int flag=judge(str);if(flag==1){printf("YES\n");}else{printf("NO\n");}}system("pause"); // 防止运行后自动退出，需头文件stdlib.hreturn 0;
}

标答

#include <cstdio>const int MAXN = 500;
const int MAXL = 11;
char str[MAXN][MAXL], num = 0;int main() {while (scanf("%s", str[num]) != EOF) {num++;}for (int i = num - 1; i >= 0; i--) {printf("%s", str[i]);if (i > 0) {printf(" ");}}return 0;
}