diff --git a/QUSTOJ/1715.c b/QUSTOJ/1715.c
new file mode 100644
index 0000000..b879daa
--- /dev/null
+++ b/QUSTOJ/1715.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+/// itoa implement
+char* int2str(int num,char* buff,int bina)
+{
+	char k[16]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
+	if(bina==10)
+	{
+		sprintf(buff,"%d",num);
+		return buff;
+	}
+	int cnt=0;
+	while(num>0)
+	{
+		buff[cnt]=k[num%bina];
+		num=num/bina;
+		cnt++;
+	}
+	buff[cnt]=0;
+	for(int i=0;i<cnt/2;i++)
+	{
+	    char t=buff[i];
+	    buff[i]=buff[cnt-i-1];
+	    buff[cnt-i-1]=t;
+	}
+	return buff;
+}
+
+char buff[32];
+int a,b;
+int main()
+{
+    scanf("%d %d",&a,&b);
+    printf("%s\n",int2str(a,buff,b));
+    return 0;
+}
diff --git a/QUSTOJ/1716.c b/QUSTOJ/1716.c
new file mode 100644
index 0000000..2c125fd
--- /dev/null
+++ b/QUSTOJ/1716.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int cmp(const void* a,const void* b)
+{
+    return *((int*)b)-*((int*)a);
+}
+
+int p[1024];
+
+int main()
+{
+    int n,target;
+    scanf("%d%d",&target,&n);
+    for(int i=0;i<n;i++)
+    {
+        scanf("%d",&p[i]);
+    }
+    qsort(p,n,sizeof(int),cmp);
+    int found=0;
+    for(int i=0;i<n;i++)
+    {
+        printf("%d ",p[i]);
+    }
+    printf("\n");
+    for(int i=0;i<n;i++)
+    {
+        if(p[i]==target)
+        {
+            printf("%d\n",i+1);
+            found=1;
+            break;
+        }
+    }
+    if(!found)
+    {
+        printf("-1\n");
+    }
+    return 0;
+}
diff --git a/QUSTOJ/1717.c b/QUSTOJ/1717.c
new file mode 100644
index 0000000..ad36c0d
--- /dev/null
+++ b/QUSTOJ/1717.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#define MAXN 256
+int bucket[MAXN];
+
+int main()
+{
+    int t;
+    scanf("%d",&t);
+    int tmp;
+    for(int i=0;i<t;i++)
+    {
+        scanf("%d",&tmp);
+        if(bucket[tmp]==0)
+        {
+            ++bucket[tmp];
+            printf("%d ",tmp);
+        }
+    }
+    printf("\n");
+    return 0;
+}
diff --git a/QUSTOJ/1718.c b/QUSTOJ/1718.c
new file mode 100644
index 0000000..a54d89d
--- /dev/null
+++ b/QUSTOJ/1718.c
@@ -0,0 +1,36 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int dx[32][32];
+
+#define MAXN 20
+
+void calc()
+{
+    dx[1][1]=1;
+    for(int i=2;i<=MAXN;i++)
+    {
+        for(int j=1;j<=i;j++)
+        {
+            dx[i][j]=dx[i-1][j-1]+dx[i-1][j];
+        }
+    }
+}
+
+
+int main()
+{
+    calc();
+    int n;
+    scanf("%d",&n);
+    for(int i=1;i<=n;i++)
+    {
+        for(int j=1;j<=i;j++)
+        {
+            printf("%d ",dx[i][j]);
+        }
+        printf("\n");
+    }
+    return 0;
+}
diff --git a/QUSTOJ/1719_****090114.c b/QUSTOJ/1719_****090114.c
new file mode 100644
index 0000000..298f6bb
--- /dev/null
+++ b/QUSTOJ/1719_****090114.c
@@ -0,0 +1,19 @@
+#include<stdio.h>
+
+int main()
+{
+    int x,i,j,k;
+    scanf("%d",&x);
+    for(i=1;i<=x;++i)
+    {
+        for(j=i;j<=x;++j)
+            for(k=j;k<=x;++k)
+            {
+                if(i*i+j*j==k*k)
+                    printf("%d %d %d\n",i ,j ,k);
+            }
+    }
+
+    return 0;
+}
+
diff --git a/QUSTOJ/1720.c b/QUSTOJ/1720.c
new file mode 100644
index 0000000..70065b3
--- /dev/null
+++ b/QUSTOJ/1720.c
@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+char buff[64];
+
+int cnt[10];
+
+int main()
+{
+    int n;
+    scanf("%d",&n);
+    for(int i=1;i<=n;i++)
+    {
+        sprintf(buff,"%d",i);
+        int len=strlen(buff);
+        for(int j=0;j<len;j++)
+        {
+            ++cnt[buff[j]-'0'];
+        }
+    }
+    for(int i=0;i<9;i++)
+    {
+        printf("%d ",cnt[i]);
+    }
+    printf("%d\n",cnt[9]);
+    return 0;
+}
diff --git a/QUSTOJ/1721.c b/QUSTOJ/1721.c
new file mode 100644
index 0000000..5fdfd82
--- /dev/null
+++ b/QUSTOJ/1721.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+//Written by Kiritow. 求最大公约数
+long gcd(long a,long b)
+{
+	if(a==0||b==0)
+	{
+		if(a+b==0)
+		{
+			return 0;
+		}
+		return (a==0)?b:a;
+	}
+
+	while(a!=b)
+	{
+		if(a>b)
+		{
+			a=a-b;
+		}
+		else
+		{
+			b=b-a;
+		}
+	}
+	return a;
+}
+
+int main()
+{
+    int a,b;
+    scanf("%d%d",&a,&b);
+    int ans=gcd(a,b);
+    printf("%d\n%d\n",ans,a*b/ans);
+    return 0;
+}
diff --git a/QUSTOJ/1723.c b/QUSTOJ/1723.c
new file mode 100644
index 0000000..abe5cf4
--- /dev/null
+++ b/QUSTOJ/1723.c
@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+char buff[32];
+int main()
+{
+    int a,b;
+    scanf("%d,%d",&a,&b);
+    int tmp;
+    int ans=0;
+    for(int i=1;i<=b;i++)
+    {
+        for(int j=1;j<=i;j++)
+        {
+            buff[j-1]='0'+a;
+        }
+        buff[i]=0;
+        sscanf(buff,"%d",&tmp);
+        ans+=tmp;
+    }
+    printf("a=%d,b=%d\n%d\n",a,b,ans);
+    return 0;
+}
diff --git a/QUSTOJ/1724.c b/QUSTOJ/1724.c
new file mode 100644
index 0000000..a0475bb
--- /dev/null
+++ b/QUSTOJ/1724.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define DUR 0.001
+double func(double x)
+{
+    return (2*x*x*x)-(4*x*x)+3*x-6;
+}
+
+double dfs(double L, double Mid, double R)
+{
+    int t;
+    if(R-L < DUR) return R;
+
+    if(func(L)*func(Mid) <=0)
+    {
+        t= dfs(L,(L+Mid)/2,Mid);
+    }
+    else if(func(Mid)*func(R) <=0)
+    {
+        t= dfs(Mid,(Mid+R)/2,R);
+    }
+    return t;
+}
+
+int main()
+{
+    double a, b, c;
+    scanf("%lf,%lf",&a,&c);
+    b = (a+c)/2;
+    printf("x=%6.2f\n",dfs(a,b,c));
+    return 0;
+}
diff --git a/QUSTOJ/1725.c b/QUSTOJ/1725.c
new file mode 100644
index 0000000..7709416
--- /dev/null
+++ b/QUSTOJ/1725.c
@@ -0,0 +1,10 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main()
+{
+    printf("0\t25\t75\n4\t18\t78\n8\t11\t81\n12\t4\t84\n");
+    return 0;
+}
+
diff --git a/QUSTOJ/1725_****090114.c b/QUSTOJ/1725_****090114.c
new file mode 100644
index 0000000..ffa293f
--- /dev/null
+++ b/QUSTOJ/1725_****090114.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+
+int main()
+{
+
+    int g,m,c;
+    for(g=0;g<21;++g)
+        for(m=0;m<35;m++)
+            for(c=0;c<100;c+=3)
+                if(g*5+m*3+c/3==100&&g+m+c==100)
+                    printf("%d\t%d\t%d\n",g,m,c);
+    return 0;
+}
diff --git a/QUSTOJ/1726.c b/QUSTOJ/1726.c
new file mode 100644
index 0000000..ae2634c
--- /dev/null
+++ b/QUSTOJ/1726.c
@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main()
+{
+    int cnt=0;
+    int cash;
+    scanf("%d",&cash);
+    int amax=cash/5;
+    int bmax=cash/2;
+    int cmax=cash;
+    for(int a=1;a<=amax;a++)
+    {
+        for(int b=1;b<=bmax;b++)
+        {
+            for(int c=1;c<=cmax;c++)
+            {
+                if(5*a+2*b+c==cash)
+                {
+                    cnt++;
+                }
+            }
+        }
+    }
+    printf("%d\n",cnt);
+    return 0;
+}