问移位和重组阵列

EN

int index = -1;

// find the positon of 'a' in the array
for (int i = 0; i <= (LRU_frame.length - 1); i++) {
    if (LRU_frame[i] == a) {
        index = i;
        break;
    }
}

// if it is present, do roughly the same thing as before
if (index > -1) {
    for (int i = (index - 1); i >= 0; i--) {
        LRU_frame[i + 1] = LRU_frame[i];
    }
    LRU_frame[0] = a;
}

// declaration
ArrayList<Integer> LRU_frame = new ArrayList<Integer>();

...

if (LRU_frame.contains(a)) {
    LRU_frame.remove((Integer) a);
    LRU_frame.add(0, a);
}

public static void LRU_shiftPageRef(char a) {
    int index = indexOf(a);
    if (index == -1) {
        //not currently in array so create a new array 1 bigger than existing with a in newArray[0] or ignore depending on functionality required.
    } else if (index > 0) {
        //Set first entry as a and shift existing entries right
        char insertChar = a;
        char nextChar = LRU_frame[0];
        for (int i =0; i < index; i++) {
             LRU_frame[i] = insertChar;
             insertChar = nextChar;
             nextChar = LRU_frame[i+1];
        }
        LRU_frame[index] = insertChar;
    } else {
        //do nothing a is already at first position
    }
}

public static int indexOf(char a) {
    for (int i=0; i < LRU_frame.length; i++) {
        if (LRU_frame[i] == a) {
            return i;
        }
    }
    return -1;
}