diff --git a/code_study/Baekjoon/c/1018.c b/code_study/Baekjoon/c/1018.c
new file mode 100644
index 0000000..83b6585
--- /dev/null
+++ b/code_study/Baekjoon/c/1018.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+int main() {
+    char board[51][51];
+    int N, M, cnt1, cnt2, min, res=64;
+    scanf("%d %d",&N,&M);
+    for(int i=0; i<N; i++) {
+        scanf("%s",board[i]);
+    }
+
+    for(int i=0; i<N-7; i++) {
+        for(int j=0; j<M-7; j++) {
+            cnt1 = 0;
+            cnt2 = 0;
+            for(int n=0; n<8; n++) {
+                for(int m=0; m<8; m++) {
+                    if((n+m)%2==0){
+                        if(board[i+n][j+m]!='W') cnt1++;
+                        if(board[i+n][j+m]!='B') cnt2++;
+                    }
+                    else{
+                        if(board[i+n][j+m]!='B') cnt1++;
+                        if(board[i+n][j+m]!='W') cnt2++;
+                    }
+                }
+            }
+            min = cnt1>cnt2 ? cnt2 : cnt1;
+            if(min<res) {
+                if(min==0) {
+                    printf("0\n");
+                    return 0;
+                }
+                res = min;
+            }
+        }
+    }
+
+    printf("%d\n", res);
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/1436.c b/code_study/Baekjoon/c/1436.c
new file mode 100644
index 0000000..d2e459a
--- /dev/null
+++ b/code_study/Baekjoon/c/1436.c
@@ -0,0 +1,26 @@
+#include <stdio.h>
+
+int main() {
+    int N;
+    scanf("%d",&N);
+
+    char Str[8];
+    int n=666, cnt=0;
+    
+    while(1) {
+        sprintf(Str,"%d", n);
+        for(int i=0; Str[i+2]!='\0'; i++) {
+            if(Str[i]=='6' && Str[i+1]=='6' && Str[i+2]=='6') {
+                cnt++;
+                if(cnt==N) {
+                    printf("%s\n",Str);
+                    return 0;
+                }
+                break;
+            }
+        }
+        n++;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/19532.c b/code_study/Baekjoon/c/19532.c
new file mode 100644
index 0000000..5bdacdb
--- /dev/null
+++ b/code_study/Baekjoon/c/19532.c
@@ -0,0 +1,31 @@
+#include <stdio.h>
+
+int main() {
+    int a,b,c,d,e,f,temp,x,y;
+    scanf("%d %d %d %d %d %d",&a,&b,&c,&d,&e,&f);
+
+    for(x=-999; x<1000; x++) {
+        if(b==0) {
+            if(a*x != c || e==0) continue;
+            temp = f - d*x;
+            if(temp%e==0) {
+                y = temp / e;
+            }
+            else continue;
+        }
+        else {
+            temp = c - a*x;
+            if(temp%b==0) {
+                y = temp / b;
+            }
+            else continue;
+        }
+
+        if(d*x+e*y==f){
+            printf("%d %d\n", x,y);
+            return 0;
+        }
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/2231.c b/code_study/Baekjoon/c/2231.c
new file mode 100644
index 0000000..ce6245c
--- /dev/null
+++ b/code_study/Baekjoon/c/2231.c
@@ -0,0 +1,31 @@
+#include <stdio.h>
+
+int main() {
+    int N;
+    scanf("%d",&N);
+
+    int n=N, cnt=0;
+    while(n!=0) {
+        cnt++;
+        n /=10;
+    }
+
+    int start = N - 9*cnt < 1 ? 1 : N - 9*cnt;
+    for(int i=start; i<N; i++) {
+        int res_sum=0, num = i;
+        while(num!=0) {
+            res_sum += num%10;
+            num/=10;
+        }
+        res_sum += i;
+
+        if(res_sum==N) {
+            printf("%d\n",i);
+            return 0;
+        }
+    }    
+
+    printf("0\n");
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/2798.c b/code_study/Baekjoon/c/2798.c
new file mode 100644
index 0000000..00f3006
--- /dev/null
+++ b/code_study/Baekjoon/c/2798.c
@@ -0,0 +1,33 @@
+#include <stdio.h>
+
+int main() {
+    int N, M, flag=0, sum_temp, result=0;
+    int arr[100];
+    scanf("%d %d",&N, &M);
+    for(int i=0; i<N; i++) {
+        scanf("%d",arr+i);
+    }
+
+    for(int i=0; i<N; i++) {
+        if(flag) break;
+        for(int j=i+1; j<N; j++) {
+            if(flag) break;
+            for(int k=j+1; k<N; k++) {
+                sum_temp = arr[i] + arr[j] + arr[k];
+                if(sum_temp <= M) {
+                    if(sum_temp > result) {
+                        result = sum_temp;
+                        if(result==M) {
+                            flag = 1;
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    printf("%d\n",result);
+
+    return 0;
+}
\ No newline at end of file
diff --git a/code_study/Baekjoon/c/2839.c b/code_study/Baekjoon/c/2839.c
new file mode 100644
index 0000000..f99f76e
--- /dev/null
+++ b/code_study/Baekjoon/c/2839.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+int main() {
+    int N;
+    scanf("%d",&N);
+
+    int three, five = N/5;
+    while(five!=-1) {
+        if( (N-five*5)%3 == 0 ) {
+            three = (N-five*5)/3;
+            printf("%d\n",three+five);
+            return 0;
+        }
+        five--;
+    }
+
+    printf("-1\n");
+
+    return 0;
+}
\ No newline at end of file