一维 二维求前缀和、差分

 final static int N=100010;
    public static void main(String[] args) {
        int []arr=new int[N];
        int []sum=new int[N];
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        int m=sc.nextInt();
        for (int i = 1; i <=n; i++) {
            arr[i]= sc.nextInt();
        }
        for (int i = 1; i <=n; i++) {
            sum[i]=sum[i-1]+arr[i];
        }
        while (m--!=0){
            int l=sc.nextInt();
            int r=sc.nextInt();
            System.out.println(sum[r]-sum[l-1]);
        }
    }

final static int N=1010,M=1010;
    public static void main(String[] args) {
    int [][]arr=new int[N][M];
    int [][]s=new int[N][M];
    Scanner sc=new Scanner(System.in);
    int n=sc.nextInt();
    int m=sc.nextInt();
    int q=sc.nextInt();
        for (int i = 1; i <=n; i++) {
            for (int j =1; j <=m; j++) {
                arr[i][j]= sc.nextInt();
            }
        }
        for (int i = 1; i <=n; i++) {
            for (int j = 1; j <=m; j++) {
                s[i][j]=s[i-1][j]+s[i][j-1]-s[i-1][j-1]+arr[i][j];
            }
        }
        while (q--!=0){
            int x1=sc.nextInt();
            int y1=sc.nextInt();
            int x2=sc.nextInt();
            int y2=sc.nextInt();
            System.out.println(s[x2][y2]-s[x1-1][y2]-s[x2][y1-1]+s[x1-1][y1-1]);
        }
    }

    final static int N=100010;
    static int [] s=new int[N];
    public static void main(String[] args) {
        int []arr=new int[N];
      Scanner sc=new Scanner(System.in);
      int n=sc.nextInt(),m= sc.nextInt();
        for (int i = 1; i <=n; i++) {
            arr[i]= sc.nextInt();
        }
        for (int i = 1; i <=n; i++) {
            insert(i,i,arr[i]);
        }
        while (m--!=0){
            int l=sc.nextInt(),r=sc.nextInt(),c=sc.nextInt();
            insert(l,r,c);
        }
        for (int i=1; i <=n; i++)  s[i]+=s[i-1];
        for(int i=1;i<=n;i++)  System.out.print(s[i]+" ");
        System.out.println();
    }
    public static void insert(int l,int r,int c){
        s[l]+=c;
        s[r+1]-=c;
    }

    final static int N=1010;
    static int [][]S=new int[N][N];
    public static void main(String[] args) {
    Scanner sc=new Scanner(System.in);
    int [][]arr=new int[N][N];
    int n= sc.nextInt(),m= sc.nextInt(),q= sc.nextInt();
        for (int i =1; i <=n; i++) {
            for (int j =1; j <=m; j++) {
                arr[i][j]= sc.nextInt();//读入原始数组
                insert(i,j,i,j,arr[i][j]);//构建差分数组S
            }
        }
        while (q-->0){
            int x1= sc.nextInt(),y1= sc.nextInt(),x2= sc.nextInt(),y2= sc.nextInt(),c= sc.nextInt();
            insert(x1,y1,x2,y2,c);
        }
        for (int i =1; i <=n; i++) {
            for (int j =1; j <=m; j++) {
               S[i][j]+=S[i][j-1]+S[i-1][j]-S[i-1][j-1];//求差分数组的前n项和
                System.out.print(S[i][j]+" ");//输出最后结果
            }
            System.out.println();
        }
    }
    public static void insert(int x1,int y1,int x2,int y2,int c){
        S[x1][y1]+=c;
        S[x2+1][y1]-=c;
        S[x1][y2+1]-=c;
        S[x2+1][y2+1]+=c;
    }