added sudoku solver and plagiarism detector in c

C/plagiarism_detector .c

@@ -0,0 +1,80 @@
+#include<stdio.h>
+#include<stdlib.h>
+typedef struct node{
+    int data;
+    struct node * next;
+}NODE;
+void printList(NODE *);//function to print the solution
+NODE* input();//Function to take input
+NODE* solve(NODE*);//function to solve the problem
+
+NODE* createNode(int);
+NODE* solve(NODE*);
+int main(){
+    NODE* head=input();
+    printList(solve(head));
+    return 0;
+}
+NODE* solve(NODE* A){
+    if(A==NULL||A->next==NULL)
+        return A;
+    NODE* ptr=A,*pre=A->next,*root=createNode(-1),*ans=root;
+    int flag;
+    while(pre!=NULL){
+        flag=0;
+        if(ptr->data==pre->data){
+            while(pre!=NULL&&ptr->data==pre->data){
+                ptr=pre;
+                pre=pre->next;
+            }
+            flag=1;
+        }
+        else{
+            ans->next=ptr;
+            ans=ans->next;
+        }
+        ptr=pre;
+        if(pre)
+            pre=pre->next;
+        if(flag==1&&pre==NULL){
+            ans->next=ptr;
+            ans=ans->next;
+        }
+    }
+    //if(root->next!=NULL)
+        return root->next;
+}
+void printList(NODE* head){
+    NODE* ptr=head;
+    if(head==NULL)
+        return;
+    while(ptr!=NULL){
+        if(ptr!=head)
+            printf("->");
+        printf("%d",ptr->data);
+        ptr=ptr->next;
+    }
+    printf("\n");
+}//Fuction used to print the linked list
+NODE* createNode(int dt){
+    NODE* n=(NODE*)malloc(sizeof(NODE));
+    n->data=dt;
+    n->next=NULL;
+    return n;
+}//Function that creates and returns a pointer to a NODE
+NODE* input(){
+    NODE* head=NULL,*tail=NULL,*pt;
+    int num,n;
+    scanf("%d",&n);
+    for(int i=0;i<n;i++){
+        scanf("%d",&num);
+        pt=createNode(num);
+        if(head==NULL)
+            head=tail=pt;
+        else{
+            tail->next=pt;
+            tail=pt;
+        }
+    }
+    return head;
+}//function that takes in the input in the form of a linked list and returns the head

C/sudoku .c

@@ -0,0 +1,70 @@
+#include <stdio.h>
+
+
+const int M=144;
+int N, R, C;
+
+int OKrow(int a[M], int x, int y, int v) {
+	int j;
+	for(j=0; j<N; j++)
+		if(a[x*N+j] == v)
+			return 0;
+	return 1;
+}
+int OKcol(int a[M], int x, int y, int v) {
+	int i;
+	for(i=0; i<N; i++)
+		if(a[i*N+y] == v)
+			return 0;
+	return 1;
+}
+int OKbox(int a[M], int x, int y, int v) {
+	int bi=x/R, bj=y/C, i, j;
+	for(i=0; i<R; i++)
+		for(j=0; j<C; j++)
+			if(a[(i + bi*R)*N + (j + bj*C)] == v)
+				return 0;
+	return 1;
+}
+int OK(int a[M], int x, int y, int v) {
+	return OKrow(a,x,y,v) && OKcol(a,x,y,v) && OKbox(a,x,y,v);
+}
+
+void print(int a[M]) {
+	int i, j;
+	for(i=0; i<N; i++)
+		for(j=0; j<N; j++)
+			printf("%d%c", a[i*N+j], (j==N-1 ? '\n':' '));
+}
+
+int solve(int a[M]) {
+	int i, j, v, rem=0;
+	for(i=0; i<N; i++) {
+		for(j=0; j<N; j++) {
+			if(a[i*N+j] == 0) {
+				rem = 1;
+				for(v=1; v<=N; v++) {
+					if(OK(a,i,j,v)) {
+						a[i*N+j] = v;
+						if(solve(a)) return 1;
+						a[i*N+j] = 0;
+					}
+				}
+			}
+		}
+	}
+	if(rem == 0) return 1;
+	return 0;
+}
+
+int main() {
+	scanf("%d%d%d", &N, &R, &C);
+	int a[M], i, j;
+	for(i=0; i<N; i++)
+		for(j=0; j<N; j++)
+			scanf("%d", &a[i*N+j]);
+
+	if(solve(a)) print(a);
+	else printf("Invalid\n");
+	return 0;
+}