Simplify struct declarations of C.

Use PascalCase for all structs in C.
SImplify n_queens.c
Format C code for chapter of graph.

codes/c/chapter_dynamic_programming/climbing_stairs_backtrack.c

@@ -28,7 +28,7 @@ int climbingStairsBacktrack(int n) {
     int choices[2] = {1, 2}; // 可选择向上爬 1 或 2 阶
     int state = 0;           // 从第 0 阶开始爬
     int *res = (int *)malloc(sizeof(int));
-    *res = 0;                // 使用 res[0] 记录方案数量
+    *res = 0; // 使用 res[0] 记录方案数量
     int len = sizeof(choices) / sizeof(int);
     backtrack(choices, state, n, res, len);
     int result = *res;

codes/c/chapter_dynamic_programming/climbing_stairs_dfs_mem.c

@@ -36,7 +36,7 @@ int climbingStairsDFSMem(int n) {
 /* Driver Code */
 int main() {
     int n = 9;
-    
+
     int res = climbingStairsDFSMem(n);
     printf("爬 %d 阶楼梯共有 %d 种方案\n", n, res);
 

codes/c/chapter_dynamic_programming/min_cost_climbing_stairs_dp.c

@@ -48,8 +48,10 @@ int main() {
     int costSize = sizeof(cost) / sizeof(cost[0]);
     printf("输入楼梯的代价列表为 [");
     for (int i = 0; i < costSize; i++) {
-        if (i != costSize - 1) printf("%d, ", cost[i]);
-        else printf("%d", cost[i]);
+        if (i != costSize - 1)
+            printf("%d, ", cost[i]);
+        else
+            printf("%d", cost[i]);
     }
     printf("]\n");